WorldWideScience

Sample records for net heat storage

  1. Solar Energy: Heat Storage.

    Science.gov (United States)

    Knapp, Henry H., III

    This module on heat storage is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

  2. Solar Heating System with Building-Integrated Heat Storage

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

  3. Calcium bromide hydration for heat storage systems

    OpenAIRE

    Ai Niwa; Noriyuki Kobayashi

    2015-01-01

    A chemical reaction is a common and simple way to produce heat for a heat storage system. The reaction produces heat energy without the use of electricity or fuel. The goal of this study was to develop a heat storage system for use in automobiles, which is able to provide heat rapidly via a hydration reaction. A heat storage system without an evaporator stores high-density heat and has a high heat output rate since the solid–liquid product that is formed is transferred as a heat medium to the...

  4. Calcium bromide hydration for heat storage systems

    Directory of Open Access Journals (Sweden)

    Ai Niwa

    2015-12-01

    Full Text Available A chemical reaction is a common and simple way to produce heat for a heat storage system. The reaction produces heat energy without the use of electricity or fuel. The goal of this study was to develop a heat storage system for use in automobiles, which is able to provide heat rapidly via a hydration reaction. A heat storage system without an evaporator stores high-density heat and has a high heat output rate since the solid–liquid product that is formed is transferred as a heat medium to the object that requires heat. The exothermic heat produced from the solid–liquid reaction was measured, and the relationship between the equivalence ratio and the reaction heat was evaluated. The heat output and heat recovered by the heat storage system, which comprised a reaction vessel and a heat exchanger, were measured. We selected solid CaBr2 because it was the best metal halide for a hydration reaction and had a high heat yield from the dissolution reaction. With this system, we were able to achieve a heat recovery rate of 582 kJ/L-H2O. We found no degradation in the chemical composition of CaBr2 after it being recycled 100 times.

  5. Heat storage in alloy transformations

    Science.gov (United States)

    Birchenall, C. E.

    1980-01-01

    The feasibility of using metal alloys as thermal energy storage media was investigated. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases were determined. A new method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation. The method and apparatus are discussed and the experimental results are presented for aluminum and two aluminum-eutectic alloys. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide was identified as a promising containment material and surface-coated iron alloys were also evaluated. System considerations that are pertinent if alloy eutectics are used as thermal energy storage media are discussed. Potential applications to solar receivers and industrial furnaces are illustrated schematically.

  6. Heat storage in the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Sastry, J.S.

    Heat storage in the Andaman Sea in upper 20 m, where a strong halocline seems to inhibit vertical heat transport has been evaluated and discussed in relation to the other parameters of heat budget. Estimation of annual evaporation gives rise to 137...

  7. Medium Deep High Temperature Heat Storage

    Science.gov (United States)

    Bär, Kristian; Rühaak, Wolfram; Schulte, Daniel; Welsch, Bastian; Chauhan, Swarup; Homuth, Sebastian; Sass, Ingo

    2015-04-01

    Heating of buildings requires more than 25 % of the total end energy consumption in Germany. Shallow geothermal systems for indirect use as well as shallow geothermal heat storage systems like aquifer thermal energy storage (ATES) or borehole thermal energy storage (BTES) typically provide low exergy heat. The temperature levels and ranges typically require a coupling with heat pumps. By storing hot water from solar panels or thermal power stations with temperatures of up to 110 °C a medium deep high temperature heat storage (MDHTS) can be operated on relatively high temperature levels of more than 45 °C. Storage depths of 500 m to 1,500 m below surface avoid conflicts with groundwater use for drinking water or other purposes. Permeability is typically also decreasing with greater depth; especially in the crystalline basement therefore conduction becomes the dominant heat transport process. Solar-thermal charging of a MDHTS is a very beneficial option for supplying heat in urban and rural systems. Feasibility and design criteria of different system configurations (depth, distance and number of BHE) are discussed. One system is designed to store and supply heat (300 kW) for an office building. The required boreholes are located in granodioritic bedrock. Resulting from this setup several challenges have to be addressed. The drilling and completion has to be planned carefully under consideration of the geological and tectonical situation at the specific site.

  8. Lightweight Thermal Storage Heat Exchangers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR proposal aims to develop thermal energy storage heat exchangers that are significantly lighter and higher conductance than the present art which involves...

  9. Investigation of heat of fusion storage for solar low energy buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2005-01-01

    This paper describes a theoretical investigation by means of TRNSYS simulations of a partly heat loss free phase change material (PCM) storage solution for solar heating systems. The partly heat loss free storage is obtained by controlled used of super cooling in a mixture of sodium acetate and x...... for storage sizes up to 1 m3, but if the same amount of net utilised solar energy should be reached it would require a water storage that is 2 – 3 times larger.......This paper describes a theoretical investigation by means of TRNSYS simulations of a partly heat loss free phase change material (PCM) storage solution for solar heating systems. The partly heat loss free storage is obtained by controlled used of super cooling in a mixture of sodium acetate...

  10. Optimum heat storage design for SDHWsystems

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    1997-01-01

    Two simulation models have been used to analyse the heat storage design's influence on the thermal performance of solar domestic hot water systems, SDHWsystems. One model is especially designed for traditional SDHWsystems based on a heat storage design where the solar heat exchanger is a built...... analysis of the tank design's influence on the thermal performance of the systems is possible.By means of the calculations design rules for the two heat storage types are proposed.......-in spiral. The other model is especially designed for low flow SDHWsystems based on a mantle tank.The tank design's influence on the thermal performance of the SDHWsystems has been investigated in a way where only one tank parameter has been changed at a time in the calculations. In this way a direct...

  11. OPTIMUM HEAT STORAGE DESIGN FOR SDHW SYSTEMS

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    1997-01-01

    Two simulation models have been used to analyse the heat storage design’s influence on the thermal performance of solar domestic hot water (SDHW) systems. One model is especially designed for traditional SDHW systems based on a heat storage design where the solar heat exchanger is a built-in spiral....... The other model is especially designed for low flow SDHW systems based on a mantle tank.The tank design’s influence on the thermal performance of the SDHW systems has been investigated in a way where only one tank parameter has been changed at a time in the calculations. In this way a direct analysis...... of the tank design’s influence on the thermal performance of the systems is possible. By means of the calculations design rules for the two heat storage types are proposed....

  12. Fusible pellet transport and storage of heat

    Science.gov (United States)

    Bahrami, P. A.

    1982-01-01

    A new concept for both transport and storage of heat at high temperatures and heat fluxes is introduced and the first steps in analysis of its feasibility is taken. The concept utilizes the high energy storage capability of materials undergoing change of phase. The phase change material, for example a salt, is encapsulated in corrosion resistant sealed pellets and transported in a carrier fluid to heat source and storage. Calculations for heat transport from a typical solar collector indicate that the pellet mass flow rates are relatively small and that the required pumping power is only a small fraction of the energy transport capability of the system. Salts and eutectic salt mixtures as candidate phase change materials are examined and discussed. Finally, the time periods for melting or solidification of sodium chloride pellets is investigated and reported.

  13. Sulfuric acid-sulfur heat storage cycle

    Science.gov (United States)

    Norman, John H.

    1983-12-20

    A method of storing heat is provided utilizing a chemical cycle which interconverts sulfuric acid and sulfur. The method can be used to levelize the energy obtained from intermittent heat sources, such as solar collectors. Dilute sulfuric acid is concentrated by evaporation of water, and the concentrated sulfuric acid is boiled and decomposed using intense heat from the heat source, forming sulfur dioxide and oxygen. The sulfur dioxide is reacted with water in a disproportionation reaction yielding dilute sulfuric acid, which is recycled, and elemental sulfur. The sulfur has substantial potential chemical energy and represents the storage of a significant portion of the energy obtained from the heat source. The sulfur is burned whenever required to release the stored energy. A particularly advantageous use of the heat storage method is in conjunction with a solar-powered facility which uses the Bunsen reaction in a water-splitting process. The energy storage method is used to levelize the availability of solar energy while some of the sulfur dioxide produced in the heat storage reactions is converted to sulfuric acid in the Bunsen reaction.

  14. Seasonal heat storage in cogeneration systems; Saesongvaermelager i kraftvaermesystem

    Energy Technology Data Exchange (ETDEWEB)

    Zinko, Heimo; Gebremedhin, Alemayehu

    2007-07-01

    be connected to the main DH net, as in the village of Linghem. The idea is to use cheap summer excess heat for heating a new subnet by installing a suitably dimensioned transit pipe and heat storage near the village to be connected. In the case of neglecting heat costs it was shown that the storage costs must be less than 4 SEK per kWh recuperated from the storage. That means that the use of rock cavern is not economic in this case, but the use of borehole ground storage can be of interest, if the storage can be constructed in such a way that suitable high heat charging and discharging flows can be achieved

  15. Cyclic high temperature heat storage using borehole heat exchangers

    Science.gov (United States)

    Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

    2016-04-01

    The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for

  16. Attribution and mitigation of heat wave-induced urban heat storage change

    Science.gov (United States)

    Sun, Ting; Kotthaus, Simone; Li, Dan; Ward, H. C.; Gao, Zhiqiu; Ni, Guang-Heng; Grimmond, C. S. B.

    2017-11-01

    When the urban heat island (UHI) effect coincides with a heat wave (HW), thermal stress in cities is exacerbated. Understanding the surface energy balance (SEB) responses to HWs is critical for improving predictions of the synergies between UHIs and HWs. This study evaluates observed SEB characteristics in four cities (Beijing, Łódź, London and Swindon), along with their ambient meteorological conditions, for both HW and background summer climate scenarios. Using the Analytical Objective Hysteresis Model (AnOHM), particular emphasis is on the heat storage. The results demonstrate that in London and Swindon the amount of daytime heat storage and its fraction relative to the net all-wave radiation increase under HWs. Results further demonstrate that such increases are strongly tied to lower wind speeds. The effects of different UHI mitigation measures on heat storage are assessed using AnOHM. Results reveal that use of reflective materials and maintaining higher soil moisture availability can offset the adverse effects of increased heat storage.

  17. Thermodynamic Efficiency of Pumped Heat Electricity Storage

    Science.gov (United States)

    Thess, André

    2013-09-01

    Pumped heat electricity storage (PHES) has been recently suggested as a potential solution to the large-scale energy storage problem. PHES requires neither underground caverns as compressed air energy storage (CAES) nor kilometer-sized water reservoirs like pumped hydrostorage and can therefore be constructed anywhere in the world. However, since no large PHES system exists yet, and theoretical predictions are scarce, the efficiency of such systems is unknown. Here we formulate a simple thermodynamic model that predicts the efficiency of PHES as a function of the temperature of the thermal energy storage at maximum output power. The resulting equation is free of adjustable parameters and nearly as simple as the well-known Carnot formula. Our theory predicts that for storage temperatures above 400°C PHES has a higher efficiency than existing CAES and that PHES can even compete with the efficiencies predicted for advanced-adiabatic CAES.

  18. Compact seasonal PCM heat storage for solar heating systems

    DEFF Research Database (Denmark)

    Dannemand, Mark

    Space heating of buildings and preparation of domestic hot water accounts for a large part of the society’s energy consumption. Solar radiation is an abundant and renewable energy source which can be harvested by solar collectors and used to cover heating demands in the built environment....... The seasonal availability of solar energy does however not match with the heating demands in buildings which typically are large in winter periods when limited solar energy is available. Heat can be stored over a few days in water stores but continuous heat losses limits the storage periods. The possibility...... of storing heat from summer where solar energy is widely available to winter periods where the heating demands are large, allows for implementing more renewable energy in our energy system. The phase change material (PCM) sodium acetate trihydrate (SAT) melts at 58 °C. The melting process requires...

  19. Heat in the Barents Sea: transport, storage, and surface fluxes

    Directory of Open Access Journals (Sweden)

    L. H. Smedsrud

    2010-02-01

    Full Text Available A column model is set up for the Barents Sea to explore sensitivity of surface fluxes and heat storage from varying ocean heat transport. Mean monthly ocean transport and atmospheric forcing are synthesised and force the simulations. Results show that by using updated ocean transports of heat and freshwater the vertical mean hydrographic seasonal cycle can be reproduced fairly well.

    Our results indicate that the ~70 TW of heat transported to the Barents Sea by ocean currents is lost in the southern Barents Sea as latent, sensible, and long wave radiation, each contributing 23–39 TW to the total heat loss. Solar radiation adds 26 TW in the south, as there is no significant ice production.

    The northern Barents Sea receives little ocean heat transport. This leads to a mixed layer at the freezing point during winter and significant ice production. There is little net surface heat loss annually in the north. The balance is achieved by a heat loss through long wave radiation all year, removing most of the summer solar heating.

    During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. The Barents Sea responds to such large changes by adjusting temperature and heat loss. Decreasing the ocean heat transport below 50 TW starts a transition towards Arctic conditions. The heat loss in the Barents Sea depend on the effective area for cooling, and an increased heat transport leads to a spreading of warm water further north.

  20. Thermochemical heat storage - system design issues

    NARCIS (Netherlands)

    Jong, A.J. de; Trausel, F.; Finck, C.J.; Vliet, L.D. van; Cuypers, R.

    2014-01-01

    Thermochemical materials (TCMs) are a promising solution for seasonal heat storage, providing the possibility to store excess solar energy from the warm season for later use during the cold season, and with that all year long sustainable energy. With our fixed bed, vacuum reactors using zeolite as

  1. Heat Sponge: A Concept for Mass-Efficient Heat Storage

    Science.gov (United States)

    Splinter, Scott C.; Blosser, Max L.; Gifford, Andrew R.

    2008-01-01

    The heat sponge is a device for mass-efficient storage of heat. It was developed to be incorporated in the substructure of a re-entry vehicle to reduce thermal- protection-system requirements. The heat sponge consists of a liquid/vapor mixture contained within a number of miniature pressure vessels that can be embedded within a variety of different types of structures. As temperature is increased, pressure in the miniature pressure vessels also increases so that heat absorbed through vaporization of the liquid is spread over a relatively large temperature range. Using water as a working fluid, the heat-storage capacity of the liquid/vapor mixture is many times higher than that of typical structural materials and is well above that of common phase change materials over a temperature range of 200 F to 700 F. The use of pure ammonia as the working fluid provides a range of application between 432 deg R and 730 deg R, or the use of the more practical water-ammonia solution provides a range of application between 432 deg R and 1160 deg R or in between that of water and pure ammonia. Prototype heat sponges were fabricated and characterized. These heat sponges consisted of 1.0-inch-diameter, hollow, stainless-steel spheres with a wall thickness of 0.020 inches which had varying percentages of their interior volumes filled with water and a water-ammonia solution. An apparatus to measure the heat stored in these prototype heat sponges was designed, fabricated, and verified. The heat-storage capacity calculated from measured temperature histories is compared to numerical predictions.

  2. Optimisation of ceramic heat storage of stoves

    Energy Technology Data Exchange (ETDEWEB)

    Buchner, K.; Hofbauer, H. [Vienna University of Technology (Austria). Inst. of Chemical Engineering

    2003-12-01

    In order to optimise the efficiency of tile stoves with a thermal capacity of up to 10 kW using wood logs, an important task is to investigate the heat storage of such firing systems used for space heating. For a basic understanding of heat transfer and heat storage behaviour, experiments as well as numerical simulations were carried out. Within the framework of these investigations, two different types of tile stoves were tested: a single-walled stove without an air gap and a double-walled stove with an air gap. Findings show that the air gap influences the heat storage behaviour causing a smooth surface temperature distribution and a decline in efficiency on the other hand. In order to avoid this negative effect, variations of the width of the air gap, ceramic mass, material and length of the flue gas tube were carried out. To remedy the deficiencies of the double-walled design, an extension of the length of the flue gas tube by 10-14% is necessary. Dense chamotte also allow double-walled tile stoves with the same efficiency as single-walled stoves using standard chamotte. (Author)

  3. Combined solar heat and power system with a latent heat storage - system simulations for an economic assessment

    Science.gov (United States)

    Zipf, Verena; Neuhäuser, Anton

    2016-05-01

    Decentralized solar combined heat and power (CHP) systems can be economically feasible, especially when they have a thermal storage. In such systems, heat provided by solar thermal collectors is used to generate electricity and useful heat for e.g. industrial processes. For the supply of energy in times without solar irradiation, a thermal storage can be integrated. In this work, the performance of a solar CHP system using an active latent heat storage with a screw heat exchanger is investigated. Annual yield calculations are conducted in order to calculate annual energy gains and, based on them; economic assumptions are used to calculated economic numbers in order to assess the system performance. The energy savings of a solar system, compared to a system with a fossil fuel supply, are calculated. Then the net present value and the dynamic payback are calculated with these savings, the initial investment costs and the operational costs. By interpretation and comparison of these economic numbers, an optimum system design in terms of solar field size and storage size was determined. It has been shown that the utilization of such systems can be economical in remote areas without gas and grid connection. Optimal storage design parameters in terms of the temperature differences in the heat exchanger and the storage capacity have been determined which can further increase the net present value of such system.

  4. A solar heating system with annual storage

    Science.gov (United States)

    Lazzari, F.; Raffellini, G.

    1981-07-01

    A solar heated house with long term storage capability, built in Trento, Italy, is described. The one story house was built from modular components and has a total heated volume of 1130 cu m. Flat plate solar collectors with a water-antifreeze medium are located beneath the lawn, and six cylindrical underground tanks holding 130 cu m of water heated by thermal energy from the collectors are situated under the garden. The house walls have an 8 cm cavity filled with 5 cm of formaldehyde foam, yielding a heat transmission (U) of 0.37 W/sq m/deg C. The roof and ceilings are insulated with fiberglass and concrete, producing U-values of 0.46 W/sq m/deg C and 0.57 W/sq m/deg C, respectively. Heat pumps using 6 kW move thermal energy between the house and the tanks. Direct hot water heating occurs in the summer, and direct home heating when the stored water temperature exceeds 32 C. A computer model was developed which traces the annual heat flow and it is shown that the system supplies all heating requirements for the house, with electrical requirements equal to 20 percent of the annual house needs.

  5. Cooperative heat transfer and ground coupled storage system

    Science.gov (United States)

    Metz, P.D.

    A cooperative heat transfer and ground coupled storage system wherein collected solar heat energy is ground stored and permitted to radiate into the adjacent ground for storage therein over an extended period of time when such heat energy is seasonally maximally available. Thereafter, when said heat energy is seasonally minimally available and has propagated through the adjacent ground a substantial distance, the stored heat energy may be retrieved by a circumferentially arranged heat transfer means having a high rate of heat transfer.

  6. High temperature active heat exchanger research for latent heat storage

    Science.gov (United States)

    Alario, J.; Haslett, R.

    1982-02-01

    An active heat exchange method in a latent heat (salt) thermal energy storage system that prevents a low conductivity solid salt layer from forming on heat transfer surfaces was developed. An evaluation of suitable media with melting points in the temperature range of interest (250 to 400 C) limited the candidates to molten salts from the chloride, hydroxide and nitrate families, based on high storage capacity, good corrosion characteristics and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a choride eutectic (20.5KCL o 24.5NaCL o 55.MgCl2% by wt.), with a nominal melting point of 385 C. Various active heat exchange concepts were given a technical and economic comparison to a passive tube shell design for a reference application (300 MW sub t for 6 hours). Test hardware was then built for the most promising concept: a direct contact heat exchanger in which molten salt droplets are injected into a cooler counter flowing stream of liquid metal carrier fluid (lead/Bismuth).

  7. Fiscal 1993 investigational report on heat pump heat storage technology; 1993 nendo heat pump chikunetsu gijutsu ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-03-01

    This project is for an investigation into the heat pump (HP) use heat storage technology, with the aim of clarifying the present status of HP heat storage technology, the utilization status, and the developmental trend of technology and of contributing to the spread of heat energy effective use using HP heat storage technology and to the promotion of the technical development. Accordingly, the evaluation of the following was made: sensible heat (SH), latent heat (LH), chemical heat storage technology (CH), and heat storage technology (HS). Investigations were made on the sensible heat use heat storage technology of water, brine, stone, soil, etc. in terms of SH; the phase change sensible heat use heat storage technology of ice, hydrate salt, paraffins, etc. in terms of LH; hydration, hydroxide, 2-propanol pyrolysis, adsorption of silica gel, zeolite and water, and heat storage technology using metal hydride, etc. in terms of CH. In terms of HS, the following were studied and evaluated from the study results of the heat storage system in which HP is applied to the sensible heat and latent heat type heat storage technology: contribution to the power load levelling and the reduction of heat source capacity, heat recovery and the use of unused energy, improvement of the system efficiency by combining HP and heat storage technology. 24 refs., 242 figs., 56 tabs.

  8. Distributed Generation with Heat Recovery and Storage

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

    2006-06-16

    Electricity produced by distributed energy resources (DER)located close to end-use loads has the potential to meet consumerrequirements more efficiently than the existing centralized grid.Installation of DER allows consumers to circumvent the costs associatedwith transmission congestion and other non-energy costs of electricitydelivery and potentially to take advantage of market opportunities topurchase energy when attractive. On-site, single-cycle thermal powergeneration is typically less efficient than central station generation,but by avoiding non-fuel costs of grid power and by utilizing combinedheat and power (CHP) applications, i.e., recovering heat from small-scaleon-site thermal generation to displace fuel purchases, DER can becomeattractive to a strictly cost-minimizing consumer. In previous efforts,the decisions facing typical commercial consumers have been addressedusing a mixed-integer linear program, the DER Customer Adoption Model(DER-CAM). Given the site s energy loads, utility tariff structure, andinformation (both technical and financial) on candidate DER technologies,DER-CAM minimizes the overall energy cost for a test year by selectingthe units to install and determining their hourly operating schedules. Inthis paper, the capabilities of DER-CAM are enhanced by the inclusion ofthe option to store recovered low-grade heat. By being able to keep aninventory of heat for use in subsequent periods, sites are able to lowercosts even further by reducing lucrative peak-shaving generation whilerelying on storage to meet heat loads. This and other effects of storageare demonstrated by analysis of five typical commercial buildings in SanFrancisco, California, USA, and an estimate of the cost per unit capacityof heat storage is calculated.

  9. Investigation on Solar Heating System with Building-Integrated Heat Storage

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

  10. Integration of Decentralized Thermal Storages Within District Heating (DH) Networks

    Science.gov (United States)

    Schuchardt, Georg K.

    2016-12-01

    Thermal Storages and Thermal Accumulators are an important component within District Heating (DH) systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized) and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

  11. Is Ocean Heat Storage Presently Knowable?

    Science.gov (United States)

    Rogers, N. L.

    2012-12-01

    Ocean heat storage plays a key role in predictions of global warming. The oceans' great thermal inertia moderates any radiative energy imbalance. A number of authors have suggested that most ocean heat storage takes place in the upper 700 meters. With the deployment of the Argo system in 2003 and the subsequent failure to detect the expected ocean warming investigators started to look deeper, down to 2000 meters. A mostly ignored problem with using ocean heat below the tropical/ temperate thermocline to measure current energy imbalances is that, as revealed by tracer studies, below thermocline water is old water that has not been in good thermal communication with the atmosphere for hundreds of years. The thermocline can be thought of as a collision between the mixed layer and very old and cold water that is rising from the abyss in an elevator-like fashion, at a rate that is uncertain but perhaps a few meters per year. The elevator is driven by dense water that, in the polar regions sinks into the abyss. A slow downward flow of heat from vertical mixing, driven by currents and tides, warms the bottom water, thus making room for new, denser, bottom water. It is helpful, as a thinking aid, to divide the Earth into the surface realm, consisting of the atmosphere and upper layer of the oceans and a second realm consisting of the deep ocean. The deep ocean may as well be in outer space since it is thermally isolated from the Earth's climate except for a very slow and presumed constant seepage of heat. Between the two realms are transition regions, the polar sinking regions and the thermocline upwelling regions. Cold water sinking warms the surface because we have removed water colder than the Earth's average temperature of 15 C from the surface realm. Upwelling cools the surface because we add water colder than the average temperature to the surface realm. The sinking and upwelling flows are equal but variable. If we draw a line at 2000 meters we can hope that the

  12. Optimal Day-to-Night Greenhouse Heat Storage

    NARCIS (Netherlands)

    Seginer, Ido; Straten, van Gerrit; Beveren, van Peter

    2016-01-01

    Day-to-night heat storage is often practiced in cold-climate greenhouses. It is suggested to manage the heat storage by considering the co-state (virtual value) of the stored heat in the on-line optimization of the greenhouse environment. Examples worked out for a periodic square-wave weather

  13. THERMOCHEMICAL HEAT STORAGE FOR CONCENTRATED SOLAR POWER

    Energy Technology Data Exchange (ETDEWEB)

    PROJECT STAFF

    2011-10-31

    Thermal energy storage (TES) is an integral part of a concentrated solar power (CSP) system. It enables plant operators to generate electricity beyond on sun hours and supply power to the grid to meet peak demand. Current CSP sensible heat storage systems employ molten salts as both the heat transfer fluid and the heat storage media. These systems have an upper operating temperature limit of around 400 C. Future TES systems are expected to operate at temperatures between 600 C to 1000 C for higher thermal efficiencies which should result in lower electricity cost. To meet future operating temperature and electricity cost requirements, a TES concept utilizing thermochemical cycles (TCs) based on multivalent solid oxides was proposed. The system employs a pair of reduction and oxidation (REDOX) reactions to store and release heat. In the storage step, hot air from the solar receiver is used to reduce the oxidation state of an oxide cation, e.g. Fe3+ to Fe2+. Heat energy is thus stored as chemical bonds and the oxide is charged. To discharge the stored energy, the reduced oxide is re-oxidized in air and heat is released. Air is used as both the heat transfer fluid and reactant and no storage of fluid is needed. This project investigated the engineering and economic feasibility of this proposed TES concept. The DOE storage cost and LCOE targets are $15/kWh and $0.09/kWh respectively. Sixteen pure oxide cycles were identified through thermodynamic calculations and literature information. Data showed the kinetics of re-oxidation of the various oxides to be a key barrier to implementing the proposed concept. A down selection was carried out based on operating temperature, materials costs and preliminary laboratory measurements. Cobalt oxide, manganese oxide and barium oxide were selected for developmental studies to improve their REDOX reaction kinetics. A novel approach utilizing mixed oxides to improve the REDOX kinetics of the selected oxides was proposed. It partially

  14. Heat storage in alloy transformations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Birchenall, C E; Gueceri, S I; Farkas, D; Labdon, M B; Nagaswami, N; Pregger, B

    1981-03-01

    A study conducted to determine the feasibility of using metal alloys as thermal energy storage media is described. The study had the following major elements: (1) the identification of congruently transforming alloys and thermochemical property measurements, (2) the development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients, (3) the development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase-change materials, and (4) the identification of materials that could be used to contain the metal alloys. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases have been determined. A new method employing x-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data that are obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase-change media. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide has been identified as a promising containment material and surface-coated iron alloys were considered.

  15. Separation of Power and Capacity In latent Heat Energy Storage

    OpenAIRE

    Pointner, H.; Steinmann, W.D.; van Eck, M.; Bachelier, C.

    2015-01-01

    The state-of-the-art latent heat energy storage system is equipped with aluminum fins at the heat exchanger pipes in order to compensate the low thermal conductivity of the phase change material (PCM). The necessary amount of fins is directly coupled to the capacity of the storage system, what makes larger systems expensive. The PCMflux concept is developed in order to realize both a controllable and a possibly more cost effectivelatent heat storage system. These aims are addressed by separat...

  16. Seasonal heat storage in underground caverns. Final report; Saisonale Waermespeicherung in Grubenraeumen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Eikmeier, B.; Mohr, M.; Unger, H.

    1999-11-01

    The solar assisted heat supply of buildings can provide an important contribution in order to achieve the targets of minimization of primary energy consumption and reduction of greenhouse gas emissions. However, the problem of the seasonal divergence between the high solar energy supply in the summer and the high demand in the winter consists; therefore seasonal heat storage is indispensable. Here, a considerable fraction of the investments must be addressed to the central reservoir. An approach towards the reduction of the investment costs for the installation of seasonal storages in the use of cavities, which are already available in mines. In the Ruhr-Area a complex net of subterranean cavities is available. For the cost estimation of solar assisted heat supply with integrated storage in mines, the reference suburban colony 'Essen-Stoppenberg' with 42 double family houses is chosen. The specific storage costs are estimated for different technical options (tunnel- or shaft storage, direct or indirect charging system). In most cases these costs are comparable to other seasonal heat storage projects. With advantageous conditions specific capital expenditures can be achieved, which are lower than those of conventional seasonal storage. However, it must be considered, that the operating costs of pit storages are expected to be higher. (orig.)

  17. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa

    2012-01-01

    are theoretically investigated by Computational Fluid Dynamics (CFD) calculations. The heat transfer rates between the PCM storage and the heating fluid/cooling fluid in the plate heat exchangers are determined. The CFD calculated temperatures are compared to measured temperatures. Based on the studies......Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change...... material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the presence of crystallization is studied experimentally. Fluid flow and heat transfer in the PCM module...

  18. Experimental investigation for the optimization of heat pipe performance in latent heat thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Ladekar, Chandrakishor; Choudhary, S. K. [RTM Nagpur University, Wardha (India); Khandare, S. S. [B. D. College of Engineering, Wardha (India)

    2017-06-15

    We investigated the optimum performance of heat pipe in Latent heat thermal energy storage (LHTES), and compared it with copper pipe. Classical plan of experimentation was used to optimize the parameters of heat pipe. Heat pipe fill ratio, evaporator section length to condenser section length ratio i.e., Heat pipe length ratio (HPLR) and heat pipe diameter, was the parameter used for optimization, as result of parametric analysis. Experiment with flow rate of 10 lit./min. was conducted for different fill ratio, HPLR and different diameter. Fill ratio of 80 %, HPLR of 0.9 and heat pipe with diameter of 18 mm showed better trend in charging and discharging. Comparison between the storage tank with optimized heat pipe and copper pipe showed almost 186 % improvement in charging and discharging time compared with the copper pipe embedded thermal storage. Heat transfer between Heat transferring fluid (HTF) and Phase change material (PCM) increased with increase in area of heat transferring media, but storage density of storage tank decreased. Storage tank with heat pipe embedded in place of copper pipe is a better option in terms of charging and discharging time as well heat storage capacity due to less heat lost. This justifies the better efficiency and effectiveness of storage tank with embedded optimized heat pipe.

  19. A solar air collector with integrated latent heat thermal storage

    Science.gov (United States)

    Charvat, Pavel; Ostry, Milan; Mauder, Tomas; Klimes, Lubomir

    2012-04-01

    Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM) was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data).

  20. Enhancing the thermal response of latent heat storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Bugaje, I.M. [Ahmadu Bello Univ., Zaria (Nigeria)

    1997-07-01

    This paper reports experiments carried out to investigate methods of enhancing the thermal response of paraffin wax heat storage tubes by incorporation of aluminium thermal conductivity promoters of various designs into the body of the wax. Heating and cooling runs were carried out and phase change times determined. It was found that the phase change time reduced significantly by orders of up to 2.2 in energy storage (heating) and 4.2 in energy recovery (cooling). Internal fins performed much better than the star matrices and expanded aluminium performed better than promoters made from aluminium sheet metal in both storage and recovery of heat. (author)

  1. Evaluation of thermal energy storage for the proposed Twin Cities District Heating system. [using cogeneration heat production and aquifiers for heat storage

    Science.gov (United States)

    Meyer, C. F.

    1980-01-01

    The technical and economic feasibility of incorporating thermal energy storage components into the proposed Twin Cities District heating project was evaluated. The technical status of the project is reviewed and conceptual designs of district heating systems with and without thermal energy storage were compared in terms of estimated capital requirements, fuel consumption, delivered energy cost, and environmental aspects. The thermal energy storage system is based on cogeneration and the storage of heat in aquifers.

  2. Wind power integration using individual heat pumps – Analysis of different heat storage options

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Mathiesen, Brian Vad; Lund, Henrik

    2012-01-01

    Significant installations of individual heat pumps are expected in future energy systems due to their economic competitiveness. This case study of the Danish energy system in 2020 with 50% wind power shows that individual heat pumps and heat storages can contribute to the integration of wind power...... reductions in excess electricity production and fuel consumption than heat accumulation tanks. Moreover, passive heat storage is found to be significantly more cost-effective than heat accumulation tanks. In terms of reducing fuel consumption of the energy system, the installation of heat pumps is the most...... important step. Adding heat storages only moderately reduces the fuel consumption. Model development has been made to facilitate a technical optimisation of individual heat pumps and heat storages in integration with the energy system....

  3. NUMERICAL ANALYSIS OF HEAT STORAGE OF SOLAR HEAT IN FLOOR CONSTRUCTION

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Holck, Ole; Svendsen, Svend

    2003-01-01

    In this paper, heat storage of solar heating in the floor construction of single-family houses is examined. A floor construction with two concrete decks is investigated. The lower is used as heat storage while the upper deck has a floor heating system. The potential for a reduction of the energy...... consumption for heating, by using heat storage in the floor construction is calculated using a dynamic simulation model of solar collector, solar tank and heat storage coupled to a building model, using the Danish Design Ref-erence Year as input. The model calculates the performance of the solar heating...... system room temperature and energy consumption. A single-family house with and without heat recovery unit on the ventilation system of 130 m² with heating demand of approximately 70 kWh/m² and 40 kWh/m² is investigated. A parametrical analysis was performed for the solar collector area, and floor layouts...

  4. Chemical heat pump and chemical energy storage system

    Science.gov (United States)

    Clark, Edward C.; Huxtable, Douglas D.

    1985-08-06

    A chemical heat pump and storage system employs sulfuric acid and water. In one form, the system includes a generator and condenser, an evaporator and absorber, aqueous acid solution storage and water storage. During a charging cycle, heat is provided to the generator from a heat source to concentrate the acid solution while heat is removed from the condenser to condense the water vapor produced in the generator. Water is then stored in the storage tank. Heat is thus stored in the form of chemical energy in the concentrated acid. The heat removed from the water vapor can be supplied to a heat load of proper temperature or can be rejected. During a discharge cycle, water in the evaporator is supplied with heat to generate water vapor, which is transmitted to the absorber where it is condensed and absorbed into the concentrated acid. Both heats of dilution and condensation of water are removed from the thus diluted acid. During the discharge cycle the system functions as a heat pump in which heat is added to the system at a low temperature and removed from the system at a high temperature. The diluted acid is stored in an acid storage tank or is routed directly to the generator for reconcentration. The generator, condenser, evaporator, and absorber all are operated under pressure conditions specified by the desired temperature levels for a given application. The storage tanks, however, can be maintained at or near ambient pressure conditions. In another form, the heat pump system is employed to provide usable heat from waste process heat by upgrading the temperature of the waste heat.

  5. System and method for determining the net output torque from a waste heat recovery system

    Science.gov (United States)

    Tricaud, Christophe; Ernst, Timothy C.; Zigan, James A.

    2016-12-13

    The disclosure provides a waste heat recovery system with a system and method for calculation of the net output torque from the waste heat recovery system. The calculation uses inputs from existing pressure and speed sensors to create a virtual pump torque sensor and a virtual expander torque sensor, and uses these sensors to provide an accurate net torque output from the WHR system.

  6. Comparing the net cost of CSP-TES to PV deployed with battery storage

    Science.gov (United States)

    Jorgenson, Jennie; Mehos, Mark; Denholm, Paul

    2016-05-01

    Concentrated solar power with thermal energy storage (CSP-TES) is a unique source of renewable energy in that its energy can be shifted over time and it can provide the electricity system with dependable generation capacity. In this study, we provide a framework to determine if the benefits of CSP-TES (shiftable energy and the ability to provide firm capacity) exceed the benefits of PV and firm capacity sources such as long-duration battery storage or conventional natural gas combustion turbines (CTs). The results of this study using current capital cost estimates indicate that a combination of PV and conventional gas CTs provides a lower net cost compared to CSP-TES and PV with batteries. Some configurations of CSP-TES have a lower net cost than PV with batteries for even the lowest battery cost estimate. Using projected capital cost targets, however, some configurations of CSP-TES have a lower net cost than PV with either option for even the lowest battery cost estimate. The net cost of CSP-TES varies with configuration, and lower solar multiples coupled with less storage are more attractive at current cost levels, due to high component costs. However, higher solar multiples show a lower net cost using projected future costs for heliostats and thermal storage materials.

  7. Integration of Decentralized Thermal Storages Within District Heating (DH Networks

    Directory of Open Access Journals (Sweden)

    Schuchardt Georg K.

    2016-12-01

    Full Text Available Thermal Storages and Thermal Accumulators are an important component within District Heating (DH systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

  8. Investigation of a heat storage for a solar heating system for combined space heating and domestic hot water supply for homeowner´s association "Bakken"

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1998-01-01

    A heat storage for a solar heating system for combined space heating and domestic hot water supply was tested in a laboratory test facility.The heat storage consist of a mantle tank with water for the heating system and of a hot water tank, which by means of thermosyphoning is heated by the water...... in the heating system. The heat storage was tested in a heat storage test facility. The most important characteristics of the heat storage were determined by means of the tests and recommendations for the design of the heat storage were given....

  9. Latent Heat Storage Through Phase Change Materials

    Indian Academy of Sciences (India)

    IAS Admin

    waste heat recovery, heating and cooling water, incorporation into textiles for human comfort, solar power plants, spacecraft thermal systems, etc. Some of the popular applications of PCM are discussed in the following sections. 2.1 Buildings. It's a well-known fact that houses with thicker walls take longer time to heat or cool ...

  10. Heat Mismatch of future Net Zero Energy Buildings within district heating areas in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    . NZEBs are characterized by having a greatly reduced energy demand that on an annual basis can be balanced out by an equivalent generation of energy from RES. Most buildings in Denmark are connected electricity grids and around half to district heating (DH) systems. Connecting buildings to larger energy...... instead of wasting the energy. The objective in this paper is find how large an area of NZEBs is to be built within DH areas and how the heat mismatch of NZEBs influence different types of Danish DH systems. In the analyses nine different scenarios are analyzed. The examination is from a technical......The long-term goal for Denmark is to develop an energy system solely based on renewable energy sources (RES) in 2050. To reach this goal energy savings in buildings are essential. Therefore, a focus on energy efficient measures in buildings and net zero energy buildings (NZEBs) have increased...

  11. Utility-controlled customer-side thermal-energy-storage tests: heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Rizy, D.T.

    1982-02-01

    Customer-side thermal energy storage has been identified as a load-management option available to the electric utility industry. The tests described here are part of the US DOE national program for the research, development, and demonstration of electric load management using utility-controlled customer-side thermal energy storage for residential load management. Five heat storage tests are described in order to: collect reliable load-research data; delineate and solve installation problems; establish maintainability; determine customer and utility acceptance; and generate cost data to determine the potential of utility-controlled customer-side storage as a load-management option. The results are expected to assist the utility industry in making local load-management decisions and to assist DOE in establishing research and development priorities in load management. The utilities tested four types of heat storage systems: central ceramic brick; concrete slab; heat pump with storage; and pressurized hot water storage. Results of installing and operating the storage systems indicate that these residential heat storage systems are not fully commercial in their present state for use as a load-management option and the technology requires further development. Also, the numerous operational problems experienced by the utilities and high costs of installing and maintaining the storage equipment resulted in poor acceptance of the technology by the utilities and customers.

  12. A control model for district heating networks with storage

    NARCIS (Netherlands)

    Scholten, Tjeert; De Persis, Claudio; Tesi, Pietro

    2014-01-01

    In [1] pressure control of hydraulic networks is investigated. We extend this work to district heating systems with storage capabilities and derive a model taking the topology of the network into account. The goal for the derived model is that it should allow for control of the storage level and

  13. Second law optimization of a sensible heat thermal energy storage system with a distributed storage element

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, M.J.

    1986-07-01

    This numerical study defined the behavior of a sensible heat thermal energy storage system whose physical design and operation had been optimized to minimize the production of thermodynamic irreversibilities. It included the effects of transient conduction within the storage material. A dimensionless set of governing equations was defined for a complete storage-removal cycle that included the effects of entropy generation due to convection and viscous effects in the flowing fluid, two-dimensional transient conduction within the storage material, and to convection due to the discharged hot fluid coming to equilibrium with the environment during the storage period. A computer program was written to solve this equation set and this program was in turn controlled by a sophisticated optimization routine to determine a dimensionless storage time, flow channel half-height, and heat transfer coefficient that resulted in a minimum amount of availability destruction. The results of this analysis showed that entropy generation within the storage material due to transient conduction was a major contributor to the total thermal irreversibilities associated with the operation of a sensible heat thermal energy storage system. For the counterflow configuration and over the range of design variables examined, material entropy generation accounted for between 26% and 60% of the total thermal availability destruction that occurred during a complete storage-removal cycle. It was also shown that the storage material aspect ratio had a significant impact on the optimum design of a storage system. Its influence was second only to the fluid mass velocity.

  14. Phase Change Material Systems for High Temperature Heat Storage.

    Science.gov (United States)

    Perraudin, David Y S; Binder, Selmar R; Rezaei, Ehsan; Ortonaa, Alberto; Haussener, Sophia

    2015-01-01

    Efficient, cost effective, and stable high-temperature heat storage material systems are important in applications such as high-temperature industrial processes (metal processing, cement and glass manufacturing, etc.), or electricity storage using advanced adiabatic compressed air energy storage. Incorporating phase change media into heat storage systems provides an advantage of storing and releasing heat at nearly constant temperature, allowing steady and optimized operation of the downstream processes. The choice of, and compatibility of materials and encapsulation for the phase change section is crucial, as these must guarantee good and stable performance and long lifetime at low cost. Detailed knowledge of the material properties and stability, and the coupled heat transfer, phase change, and fluid flow are required to allow for performance and lifetime predictions. We present coupled experimental-numerical techniques allowing prediction of the long-term performance of a phase change material-based high-temperature heat storage system. The experimental investigations focus on determination of material properties (melting temperature, heat of fusion, etc.) and phase change material and encapsulation interaction (stability, interface reactions, etc.). The computational investigations focus on an understanding of the multi-mode heat transfer, fluid flow, and phase change processes in order to design the material system for enhanced performance. The importance of both the experimental and numerical approaches is highlighted and we give an example of how both approaches can be complementarily used for the investigation of long-term performance.

  15. Evaluating work/recovery schedules in terms of whole body heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, S.G. [Natural Resources Canada, Sudbury, ON (Canada). CANMET Mining and Mineral Sciences Laboratories; Stapleton, J.M.; Kenny, G.P. [Ottawa Univ., Ottawa, ON (Canada). School of Human Kinetics, Human and Environmental Physiology Research Unit; Allen, C. [Vale Inco, Copper Cliff, ON (Canada)

    2010-07-01

    This paper reported on heat stress related research aimed at better managing the heat exposure of underground miners. The potential for underground miners to experience heat stress or strain is increasing due to greater mining depth; mechanization, and a trend towards larger diesel equipment; an aging workforce; an increasing amount of personal protective equipment worn to prevent injuries (that has led to most of the miner's body being covered) and increases in the surface climate that are superimposed through the underground workplace. This paper focused on research involving metabolic heat storage and the possibility of heat strain from elevated core temperatures. It targeted work/recovery cycles and the recovery strategies between work bouts. The first study examined the cumulative change in body heat content for a moderate metabolic rate and increasing the recovery allocation as per the TLV screening criteria to offset an increase in the wet bulb globe temperature (WBGT). The second study examined strategies that could be used between work bouts and how they affect the thermoregulatory system, heat generation or losses and net cumulative heat storage. The calorimeter based work suggested that a miner's clothing may be improved to promote evaporative cooling, and that work recovery regimes could be modified to maximize recovery. 10 refs., 1 tab., 6 figs.

  16. Microencapsulated Phase-Change Materials For Storage Of Heat

    Science.gov (United States)

    Colvin, David P.

    1989-01-01

    Report describes research on engineering issues related to storage and transport of heat in slurries containing phase-change materials in microscopic capsules. Specific goal of project to develop lightweight, compact, heat-management systems used safely in inhabited areas of spacecraft. Further development of obvious potential of technology expected to lead to commercialization and use in aircraft, electronic equipment, machinery, industrial processes, and other sytems in which requirements for management of heat compete with severe restrictions on weight or volume.

  17. Aquifer thermal energy (heat and chill) storage

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, E.A. (ed.)

    1992-11-01

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  18. Efficient numerical simulation of heat storage in subsurface georeservoirs

    Science.gov (United States)

    Boockmeyer, A.; Bauer, S.

    2015-12-01

    The transition of the German energy market towards renewable energy sources, e.g. wind or solar power, requires energy storage technologies to compensate for their fluctuating production. Large amounts of energy could be stored in georeservoirs such as porous formations in the subsurface. One possibility here is to store heat with high temperatures of up to 90°C through borehole heat exchangers (BHEs) since more than 80 % of the total energy consumption in German households are used for heating and hot water supply. Within the ANGUS+ project potential environmental impacts of such heat storages are assessed and quantified. Numerical simulations are performed to predict storage capacities, storage cycle times, and induced effects. For simulation of these highly dynamic storage sites, detailed high-resolution models are required. We set up a model that accounts for all components of the BHE and verified it using experimental data. The model ensures accurate simulation results but also leads to large numerical meshes and thus high simulation times. In this work, we therefore present a numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly for use in larger scale simulations. The numerical model includes all BHE components and represents the temporal and spatial temperature distribution with an accuracy of less than 2% deviation from the fully discretized model. By changing the BHE geometry and using equivalent parameters, the simulation time is reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. Results of a sensitivity study that quantify the effects of different design and storage formation parameters on temperature distribution and storage efficiency for heat storage using multiple BHEs are then shown. It is found that storage efficiency strongly depends on the number of BHEs composing the storage site, their distance and

  19. Consumer Unit for Low Energy District Heating Net

    DEFF Research Database (Denmark)

    Paulsen, Otto; Fan, Jianhua; Furbo, Simon

    2008-01-01

    heat load on a daily basis, having a flow temperature control based on outdoor climate. The unit is designed for a near constant district heating water flow. The paper describes two concepts. The analyses are based on TRNSYS (Klein et al., 2006) simulation, supplied with laboratory verification...

  20. Testing of PCM Heat Storage Modules with Solar Collectors as Heat Source

    DEFF Research Database (Denmark)

    Englmair, Gerald; Dannemand, Mark; Johansen, Jakob Berg

    2016-01-01

    was to actively utilize the ability of the material to supercool to obtain long storage periods. The modules were charged with solar heat supplied by 22.4 m2 evacuated tubular collectors. The investigation showed that it was possible to fully charge one module within a period of 270 minutes with clear skies......A latent heat storage based on the phase change material Sodium Acetate Trihydrate (SAT) has been tested as part of a demonstration system. The full heat storage consisted of 4 individual modules each containing about 200 kg of sodium acetate trihydrate with different additives. The aim...

  1. Experimental and theoretic investigations of thermal behavior of a seasonal water pit heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Huang, Junpeng; Chatzidiakos, Angelos

    Seasonal heat storages are considered essential for district heating systems because they offer flexibility for the system to integrate different fluctuating renewable energy sources. Water pit thermal storages (PTES) have been successfully implemented in solar district heating plants in Denmark...

  2. Influence of egg pre-storage heating period and storage length on incubation results

    Directory of Open Access Journals (Sweden)

    FHA Silva

    2008-03-01

    Full Text Available This experiment aimed at evaluating the influence of different heating times of settable eggs of Cobb 500® broiler breeders before submitting them to different storage periods on egg weight loss, embryo mortality, and hatchability. A total number of 1,980 eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement, comprising nine treatments with 22 replicates of 10 eggs each. The following factors were analyzed: pre-storage heating periods (0, 6, 12 hours at 36.92°C and storage periods (4, 9, 14 days at 12.06°C. After storage, eggs were incubated under usual conditions, and were transferred to the hatcher at 442 hours of incubation. Eggs were weighed before heating, incubation, and transference to determine weight loss. Partial hatchability was determined at 480 hours, and total hatchability at 498 hours of incubation. Embryo mortality was determined in non-hatched eggs. It was concluded that heating eggs for six hour before storage improves incubation results as it decreases incubation length and late embryo mortality, therefore its use can be indicated in commercial operations. Storing eggs for 14 days and pre-heating for 14 days and pre-heating for 12 hours severely impair incubation results, and therefore are not recommended.

  3. Investigation of high capacity heat energy storage for building applications

    OpenAIRE

    Ding, Yate

    2014-01-01

    The problems of excessive consumption of fossil resources, oil shortages and greenhouse gas emissions are becoming increasingly severe. Research and development work on new methods of thermal energy storage are imminently required. To effectively store seasonal renewable energy, a novel high capacity heat storage system has been designed and evaluated/validated through laboratory experiments and numerical simulations in this research. The system is driven by direct flow evacuated tube solar c...

  4. Evaluation of Advanced Stirling Convertor Net Heat Input Correlation Methods Using a Thermal Standard

    Science.gov (United States)

    Briggs, Maxwell H.; Schifer, Nicholas A.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs), developed by Sunpower Inc. and NASA Glenn Research Center (GRC). The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot end and cold end temperatures, and specified electrical power output for a given net heat input. In an effort to improve net heat input predictions, numerous tasks have been performed which provided a more accurate value for net heat input into the ASCs, including testing validation hardware, known as the Thermal Standard, to provide a direct comparison to numerical and empirical models used to predict convertor net heat input. This validation hardware provided a comparison for scrutinizing and improving empirical correlations and numerical models of ASC-E2 net heat input. This hardware simulated the characteristics of an ASC-E2 convertor in both an operating and non-operating mode. This paper describes the Thermal Standard testing and the conclusions of the validation effort applied to the empirical correlation methods used by the Radioisotope Power System (RPS) team at NASA Glenn.

  5. Evaluation of a sulfur oxide chemical heat storage process for a steam solar electric plant

    Energy Technology Data Exchange (ETDEWEB)

    Dayan, J.; Lynn, S.; Foss, A.

    1979-07-01

    The purpose of this study was to develop and evaluate technically feasible process configurations for the use of the sulfur oxide system, 2 SO/sub 3/ reversible 2 SO/sub 2/ + O/sub 2/, in energy storage. The storage system is coupled with a conventional steam-cycle power plant. Heat for both the power plant and the storage system is supplied during sunlit hours by a field of heliostats focussed on a central solar receiver. When sunlight is not available, the storage system supplies the heat to operate the power plant. A technically feasible, relatively efficient configuration is proposed for incorporating this type of energy storage system into a solar power plant. Complete material and energy balances are presented for a base case that represents a middle range of expected operating conditions. Equipment sizes and costs were estimated for the base case to obtain an approximate value for the cost of the electricity that would be produced from such an installation. In addition, the sensitivity of the efficiency of the system to variations in design and operating conditions was determined for the most important parameters and design details. In the base case the solar tower receives heat at a net rate of 230 MW(t) for a period of eight hours. Daytime electricity is about 30 MW(e). Nighttime generation is at a rate of about 15 MW(e) for a period of sixteen hours. The overall efficiency of converting heat into electricity is about 26%. The total capital cost for the base case is estimated at about $68 million, of which about 67% is for the tower and heliostats, 11% is for the daytime power plant, and 22% is for the storage system. The average cost of the electricity produced for the base case is estimated to be about 11 cents/kW(e)-hr.

  6. Optimum heat storage design for heat integrated multipurpose batch plants

    CSIR Research Space (South Africa)

    Stamp, J

    2011-01-01

    Full Text Available Heat integration to minimise energy usage in multipurpose batch plants has been in published literature for more than two decades. In most present methods, time is fixed a priori through a known schedule, which leads to suboptimal results...

  7. Heat transfer and thermal storage in fixed and fluidized beds of phase change materials

    OpenAIRE

    Izquierdo Barrientos, Maria Asunción

    2016-01-01

    Mención Internacional en el título de doctor Thermal energy storage is a key technology for energy conservation since many energy sources are intermittent in nature. Latent heat storage is considered one of the most efficient ways of storing thermal energy because, unlike sensible heat storage, it provides a high-energy storage density with a small temperature swing. There are available many storage techniques, including sensible and latent heat storage or a combination of b...

  8. Coatings for Heat Storage Reactors with Hygroscopic Salts

    NARCIS (Netherlands)

    De Jong, A.J.; Stevens, R.; Rentrop, C.; Hoegaerts, C.

    2015-01-01

    One of the bottlenecks for realizing a commercial system for thermochemical heat storage using hygroscopic salts is corrosion induced by chemical side-reactions. E.g. when Na2S hydrates are used, we basically deal with corrosion caused by the production of the volatile H2S, threatening metal parts

  9. Day-to-night heat storage in greenhouses

    NARCIS (Netherlands)

    Seginer, Ido; Straten, van Gerrit; Beveren, van Peter J.M.

    2017-01-01

    Day-to-night heat storage using water tanks (buffers) is common practice in cold-climate greenhouses, where gas is burned during the day for carbon dioxide enrichment. In this study an optimal control approach is outlined for such a system, based on the idea that the virtual value (shadow price) of

  10. Day-to-night heat storage in greenhouses

    NARCIS (Netherlands)

    Seginer, Ido; Straten, van Gerrit; Beveren, van Peter J.M.

    2017-01-01

    Day-to-night heat storage in water tanks (buffers) is common practice in cold-climate greenhouses, where gas is burned during the day for carbon dioxide enrichment. In Part 1 of this study, an optimal control approach was outlined for such a system, the basic idea being that the virtual value

  11. Integration of solar heat storage in the ground floor; Bygningsintegreret varmelagring af solvarme i terraendaek

    Energy Technology Data Exchange (ETDEWEB)

    Weitzmann, P.; Holck, O.; Svendsen, S.

    2001-07-01

    layer are described. The model of the house used for calculations is described. Two different versions are used. One that is built according to the present day Danish Building Code, and one built according to the forthcoming Danish Building Code. The results from the simulations are shown. The foundation for the calculations are given, and the results are listed. The results include calculations of the heating demand of the house, the reduction of the heating demand as a consequence of the heat storage in the floor. For the supply of hot water the system's net gain is shown, and the percentage of the hot water supplied by the solar collector. The results are shown for the different layouts of the floor. The influence of the control system is also briefly discussed. A number of dimensioning diagrams are shown. These are based on the results from the parametrical analysis. The price and pay back time of heat storage in a floor is examined. (EHS)

  12. An experimental investigation of shell and tube latent heat storage for solar dryer using paraffin wax as heat storage material

    Directory of Open Access Journals (Sweden)

    Ashish Agarwal

    2016-03-01

    Full Text Available In the presented study the shell and tube type latent heat storage (LHS has been designed for solar dryer and paraffin wax is used as heat storage material. In the first part of the study, the thermal and heat transfer characteristics of the latent heat storage system have been evaluated during charging and discharging process using air as heat transfer fluid (HTF. In the last section of the study the effectiveness of the use of an LHS for drying of food product and also on the drying kinetics of a food product has been determined. A series of experiments were conducted to study the effects of flow rate and temperature of HTF on the charging and discharging process of LHS. The temperature distribution along the radial and longitudinal directions was obtained at different time during charging process to analyze the heat transfer phenomenon in the LHS. Thermal performance of the system is evaluated in terms of cumulative energy charged and discharged, during the charging and discharging process of LHS, respectively. Experimental results show that the LHS is suitable to supply the hot air for drying of food product during non-sunshine hours or when the intensity of solar energy is very low. Temperature gain of air in the range of 17 °C to 5 °C for approximately 10 hrs duration was achieved during discharging of LHS.

  13. Numerical Analysis of Heat Storage and Heat Conductivity in the Concrete Hollow Core Deck Element

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2011-01-01

    the overall heat transfer and heat storage in the hollow-core decks. The presented results allow comparison between detailed results from 2D-COMSOL simulations and simple 1D calculations from the whole building simulation tool such as BSim program and moreover, it is possible to validate the calculation...

  14. Experimental results of a 3 k Wh thermochemical heat storage module for space heating application

    NARCIS (Netherlands)

    Finck, C.J.; Henquet, E.M.R.; Soest, C.F.L. van; Oversloot, H.P.; Jong, A.J. de; Cuypers, R.; Spijker, J.C. van 't

    2014-01-01

    A 3 kWh thermochemical heat storage (TCS) module was built as part of an all-in house system implementation focusing on space heating application at a temperature level of 40 ºC and a temperature lift of 20 K. It has been tested and measurements showed a maximum water circuit temperature span

  15. Heat storage for a bus petrol internal-combustion engine

    Science.gov (United States)

    Vasiliev, Leonard L.; Burak, Victor S.; Kulakov, Andry G.; Mishkinis, Donatas A.; Bohan, Pavel V.

    The heat storage (HS) system for pre-heating a bus petrol internal combustion engine to starting was mathematically modelled and experimentally investigated. The development of such devices is an extremely urgent problem especially for regions with a cold climate. We discuss how HS works on the effect of absorption and rejection of heat energy at a solid-liquid phase change of a HS substance. In the first part of the paper a numerical method to calculate the HS mass-dimensional parameters and their characteristics are described. In the experimental part of the paper results are given of experiments on the pre-heating device aiding to start a carburettor engine under operational conditions and analysis of data received. Practical confirmation of the theoretical development of HS devices for a bus engine for starting by pre-heating is given.

  16. Wind power integration with heat pumps, heat storages, and electric vehicles - Energy systems analysis and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hedegaard, K.

    2013-09-15

    This PhD investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing research, the main focus is put on individual heat pumps in the residential sector (one-family houses) and the possibilities for flexible operation, using the heat storage options available. Several energy systems analyses are performed using the energy system models, Balmorel, developed at the former TSO, ElkraftSystem, and, EnergyPLAN, developed at Aalborg University. The Danish energy system towards 2030, with wind power penetrations of up to 60 %, is used as a case study in most of the analyses. Both models have been developed further, resulting in an improved representation of individual heat pumps and heat storages. An extensive model add-on for Balmorel renders it possible to optimise investment and operation of individual heat pumps and different types of heat storages, in integration with the energy system. Total costs of the energy system are minimised in the optimisation. The add-on incorporates thermal building dynamics and covers various different heat storage options: intelligent heat storage in the building structure for houses with radiator heating and floor heating, respectively, heat accumulation tanks on the space heating circuit, as well as hot water tanks. In EnergyPLAN, some of the heat storage options have been modelled in a technical optimisation that minimises fuel consumption of the energy system and utilises as much wind power as possible. The energy systems analyses reveal that in terms of supporting wind power integration, the installation of individual heat pumps is an important step, while adding heat storages to the heat pumps is less influential. When equipping the heat pumps with heat storages, only moderate system benefits can be gained. Hereof, the main system benefit is that the need for peak/reserve capacity investments can be reduced through peak load shaving; in

  17. Building physics: wood fiber plates - insulating materials as a heat storage system; Bauphysik: Holzfaserdaemmplatten - Daemmstoffe als Waermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, G.

    2006-12-13

    A high heat storage cabability is very effectful due to summer heat behaviour. Advanced heat insulating materials with high heat capacities and raw densities enable the enhancement of heat storage without losses on thermal protection. (GL)

  18. Bioactive Compounds and Fruit Quality of Green Sweet Pepper Grown under Different Colored Shade Netting during Postharvest Storage.

    Science.gov (United States)

    Mashabela, Madonna N; Selahle, Kamogelo M; Soundy, Puffy; Crosby, Kevin M; Sivakumar, Dharini

    2015-11-01

    In this study, influence of 3 types of photo-selective nets (pearl, red and yellow) and a standard black net on marketable yield, fruit quality and bioactive compounds after postharvest storage was investigated. Percentage marketable fruits were higher in green sweet peppers produced under the pearl nets. Fruits produced under the pearl nets showed higher fruit mass, firmness, chlorophyll content, ascorbic acid content, antioxidant scavenging activity after postharvest storage. Red/far red photon ratio under the pearl net could have improved the ascorbic acid content and the antioxidant scavenging activity in green peppers. Green sweet peppers grown under the pearl nets had higher hue values and maintained green color longer. Our results showed the impact of modified light quality on the bioactive compounds of green sweet pepper during postharvest storage. Green sweet peppers are rich in phytochemicals. Marketability of green sweet peppers is affected partially due to ripening after postharvest storage and decay. Maintenance of green color, fruit mass, firmness, and nutritional composition are important parameters that attract consumers. This research shows the influence of light quality during production on the fruit quality parameters and bioactive compounds after postharvest storage. © 2015 Institute of Food Technologists®

  19. Saline Cavern Adiabatic Compressed Air Energy Storage Using Sand as Heat Storage Material

    Directory of Open Access Journals (Sweden)

    Martin Haemmerle

    2017-03-01

    Full Text Available Adiabatic compressed air energy storage systems offer large energy storage capacities and power outputs beyond 100MWel. Salt production in Austria produces large caverns which are able to hold pressure up to 100 bar, thus providing low cost pressurized air storage reservoirs for adiabatic compressed air energy storage plants. In this paper the results of a feasibility study is presented, which was financed by the Austrian Research Promotion Agency, with the objective to determine the adiabatic compressed air energy storage potential of Austria’s salt caverns. The study contains designs of realisable plants with capacities between 10 and 50 MWel, applying a high temperature energy storage system currently developed at the Institute for Energy Systems and Thermodynamics in Vienna. It could be shown that the overall storage potential of Austria’s salt caverns exceeds a total of 4GWhel in the year 2030 and, assuming an adequate performance of the heat exchanger, that a 10MWel adiabatic compressed air energy storage plant in Upper Austria is currently feasible using state of the art thermal turbomachinery which is able to provide a compressor discharge temperature of 400 °C.

  20. The CellFlux Storage Concept for Increased Flexibility in Sensible Heat Storage

    OpenAIRE

    Odenthal, Christian; Steinmann, Wolf-Dieter; Eck, Markus

    2015-01-01

    Packed beds using air at atmospheric pressure as heat transferring medium are the most cost effective systems for sensible heat storage. The basic idea of the CellFlux concept is to apply this concept also for liquid and/or pressurized primary HTFs by the introduction of an intermediate working fluid cycle. A heat exchanger is used for transferring energy between the primary HTF and the intermediate air cycle which eventually transfers the energy to a packed bed. The CellFlux concept...

  1. Heat storage system utilizing phase change materials government rights

    Science.gov (United States)

    Salyer, Ival O.

    2000-09-12

    A thermal energy transport and storage system is provided which includes an evaporator containing a mixture of a first phase change material and a silica powder, and a condenser containing a second phase change material. The silica powder/PCM mixture absorbs heat energy from a source such as a solar collector such that the phase change material forms a vapor which is transported from the evaporator to the condenser, where the second phase change material melts and stores the heat energy, then releases the energy to an environmental space via a heat exchanger. The vapor is condensed to a liquid which is transported back to the evaporator. The system allows the repeated transfer of thermal energy using the heat of vaporization and condensation of the phase change material.

  2. Experimental testing of various heat transfer structures in a flat plate thermal energy storage unit

    OpenAIRE

    Johnson, Maike; Fiss, Michael; Klemm, Torsten

    2016-01-01

    For solar process heat applications with steam as the working fluid and varying application parameters, a novel latent heat storage concept has been developed using an adaptation of a flat plate heat exchanger as the storage concept. Since the pressure level in these applications usually does not exceed 30 bar, an adaptation with storage material chambers arranged between heat transfer medium chambers is possible. Phase change materials are used as the storage medium, so that the isotherma...

  3. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  4. Computational Evaluation of a Latent Heat Energy Storage System

    Science.gov (United States)

    2013-01-01

    terrestrial applications , or propellant heating for on-orbit applications ), a thermally-based energy storage system can offer significant advantages in... PCM Core - - 0.08 0.06 Silicon Inner Container 0.08 0.06 0.1 0.065 Silicon Carbide Outer Container 0.295 0.195 0.315 0.205 Graphite Insulation...represent the cooling load required to maintain the cells at the desired operating temperature. A volumetric heat sink with magnitude equal to the average

  5. A method to determine stratification efficiency of thermal energy storage processes independently from storage heat losses

    DEFF Research Database (Denmark)

    Haller, M.Y.; Yazdanshenas, Eshagh; Andersen, Elsa

    2010-01-01

    A new method for the calculation of a stratification efficiency of thermal energy storages based on the second law of thermodynamics is presented. The biasing influence of heat losses is studied theoretically and experimentally. Theoretically, it does not make a difference if the stratification...... efficiency is calculated based on entropy balances or based on exergy balances. In practice, however, exergy balances are less affected by measurement uncertainties, whereas entropy balances can not be recommended if measurement uncertainties are not corrected in a way that the energy balance of the storage...... directly, and a tank-in-tank system whose outer tank is charged and the inner tank is discharged thereafter. The new method has a great potential for the comparison of the stratification efficiencies of thermal energy storages and storage components such as stratifying devices....

  6. Modeling Pumped Thermal Energy Storage with Waste Heat Harvesting

    Science.gov (United States)

    Abarr, Miles L. Lindsey

    This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual-functionality. This dissertation first presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was +/- 0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed PTES) that uses ammonia as the working fluid. This analysis focused on the effects of hot thermal storage utilization, system pressure, and evaporator/condenser size on the system performance. This work presents the estimated performance for a proposed baseline Bot-PTES. Results of this analysis showed that all selected parameters had significant effects on efficiency, with the evaporator/condenser size having the largest effect over the selected ranges. Results for the baseline case showed stand-alone energy storage efficiencies between 51 and 66% for varying power levels and charge states, and a stand-alone bottoming efficiency of 24%. The resulting efficiencies for this case were low compared to competing technologies; however, the dual-functionality of the Bot-PTES enables it to have higher capacity factor, leading to 91-197/MWh levelized cost of energy compared to 262-284/MWh for batteries and $172-254/MWh for Compressed Air Energy Storage.

  7. Coupling Geothermal Heat Pumps with Underground Seasonal Thermal Energy Storage

    Science.gov (United States)

    2017-03-21

    United States (US). It also created the US’s only known active “full” ( warm and cold) Aquifer Thermal Energy Storage (ATES) system. This...systems in the U.S. are not designed to achieve. Deliberately engineered UTES systems not only allow for the waste heat of cooling systems and the...Ingenieure (Largest Engineering Association in Western Europe) VAV Variable Air Volume vii Page Intentionally Left

  8. Modelling of storage tanks with immersed heat exchangers

    OpenAIRE

    Cadafalch Rabasa, Jordi; Carbonell Sánchez, Daniel; Consul Serracanta, Ricard; Ruiz Mansilla, Rafael

    2015-01-01

    A model of a storage tank with an immersed serpentine heat exchanger is described and validated against experimental data available from the literature. The tank is modelled one dimensionally using the multi-node approach corrected by an energy conservative reversion elimination algorithm to prevent inverse gradient solutions to occur. A one dimensional model in the flow direction is also used for the serpentine based on control volume techniques. The serpentine is discretized in equal sized ...

  9. Analysis of selected surface characteristics and latent heat storage for passive solar space heating

    Energy Technology Data Exchange (ETDEWEB)

    Fthenakis, V.; Leigh, R.

    1981-12-01

    Results are presented of an analysis of the value of various technical improvements in the solar collector and thermal storage subsystems of passive solar residential, agricultural, and industrial systems for two regions of the country. The evaluated improvements are: decreased emissivity and increased absorptivity of absorbing surfaces, decreased reflectivity, and decreased emissivity of glazing surface, and the substitution of sensible heat storage media with phase change materials. The value of each improvement is estimated by the additional energy savings resulting from the improvement.

  10. Multiscale simulation approach to heat and mass transfer properties of nanostructured materials for sorption heat storage

    OpenAIRE

    Fasano, Matteo; Borri, Daniele; Cardellini, Annalisa; Alberghini, Matteo; Morciano, Matteo; Chiavazzo, Eliodoro; Asinari, Pietro

    2017-01-01

    Thermal storage devices are becoming crucial for the exploitation of solar energy. From the point of view of seasonal energy storage, the most promising technology is represented by adsorption thermal batteries, which allow storing energy without heat loss with time. The improvement of thermal batteries design is related to a better understating of transport phenomena occurring in the adsorption/desorption phases. In this work, we discuss an efficient computational protocol to characterize ad...

  11. Integrated heat exchanger design for a cryogenic storage tank

    Science.gov (United States)

    Fesmire, J. E.; Tomsik, T. M.; Bonner, T.; Oliveira, J. M.; Conyers, H. J.; Johnson, W. L.; Notardonato, W. U.

    2014-01-01

    Field demonstrations of liquid hydrogen technology will be undertaken for the proliferation of advanced methods and applications in the use of cryofuels. Advancements in the use of cryofuels for transportation on Earth, from Earth, or in space are envisioned for automobiles, aircraft, rockets, and spacecraft. These advancements rely on practical ways of storage, transfer, and handling of liquid hydrogen. Focusing on storage, an integrated heat exchanger system has been designed for incorporation with an existing storage tank and a reverse Brayton cycle helium refrigerator of capacity 850 watts at 20 K. The storage tank is a 125,000-liter capacity horizontal cylindrical tank, with vacuum jacket and multilayer insulation, and a small 0.6-meter diameter manway opening. Addressed are the specific design challenges associated with the small opening, complete modularity, pressure systems re-certification for lower temperature and pressure service associated with hydrogen densification, and a large 8:1 length-to-diameter ratio for distribution of the cryogenic refrigeration. The approach, problem solving, and system design and analysis for integrated heat exchanger are detailed and discussed. Implications for future space launch facilities are also identified. The objective of the field demonstration will be to test various zero-loss and densified cryofuel handling concepts for future transportation applications.

  12. Studies on a Heat Storage Container with Phase Change Material

    Science.gov (United States)

    Toyoda, Naoki; Watanabe, Koji; Watanabe, Mituo; Yanadori, Michio

    This paper deals with the heat transfer characteristics when a phase change medium discharges the storing energy to a finned tube in a heat storage container. In this experiments, the phase change medium is Calcium Chloride Hexahydrate (CaCl26H2O)with fusion temperature 28°C. The following results are obtained. 1. In solidification process of the medium, the heat discharge quantity to a finned tube is greater than that to a single tube, However, the heat dischage quantity of the finned tube does not increase inproportion to the surface area of the fin. 2. The fin effect of the finned tube decreases as the increase of the accumulative heat discharge quantity rate. 3. This reason lies in the fact that the thermal resistance of the finned tube is greater than that of the single tube. Especially, in the range of the large values of the accumulative heat discharge quantity rate, it is consiberable that the themal resistanse increases so that the ratio of the dead space of the heat transfer area increases at the contact parts of the fins and the tube.

  13. Active latent heat storage with a screw heat exchanger - experimental results for heat transfer and concept for high pressure steam

    Science.gov (United States)

    Zipf, Verena; Willert, Daniel; Neuhäuser, Anton

    2016-05-01

    An innovative active latent heat storage concept was invented and developed at Fraunhofer ISE. It uses a screw heat exchanger (SHE) for the phase change during the transport of a phase change material (PCM) from a cold to a hot tank or vice versa. This separates heat transfer and storage tank in comparison to existing concepts. A test rig has been built in order to investigate the heat transfer coefficients of the SHE during melting and crystallization of the PCM. The knowledge of these characteristics is crucial in order to assess the performance of the latent heat storage in a thermal system. The test rig contains a double shafted SHE, which is heated or cooled with thermal oil. The overall heat transfer coefficient U and the convective heat transfer coefficient on the PCM side hPCM both for charging and discharging have been calculated based on the measured data. For charging, the overall heat transfer coefficient in the tested SHE was Uch = 308 W/m2K and for discharging Udis = 210 W/m2K. Based on the values for hPCM the overall heat transfer coefficients for a larger SHE with steam as heat transfer fluid and an optimized geometry were calculated with Uch = 320 W/m2K for charging and Udis = 243 W/m2K for discharging. For pressures as high as p = 100 bar, an SHE concept has been developed, which uses an organic fluid inside the flight of the SHE as working media. With this concept, the SHE can also be deployed for very high pressure, e.g. as storage in solar thermal power plants.

  14. Preparation of fine powdered composite for latent heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Fořt, Jan, E-mail: jan.fort.1@fsv.cvut.cz; Trník, Anton, E-mail: anton.trnik@fsv.cvut.cz; Pavlíková, Milena, E-mail: milena.pavlikova@fsv.cvut.cz; Pavlík, Zbyšek, E-mail: pavlikz@fsv.cvut.cz [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic); Pomaleski, Marina, E-mail: marina-pomaleski@fsv.cvut.cz [Faculty of Civil Engineering, Architecture and Urbanism, University of Campinas, R. Saturnino de Brito 224, 13083-889 Campinas – SP (Brazil)

    2016-07-07

    Application of latent heat storage building envelope systems using phase-change materials represents an attractive method of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. This study deals with a preparation of a new type of powdered phase change composite material for thermal energy storage. The idea of a composite is based upon the impregnation of a natural silicate material by a reasonably priced commercially produced pure phase change material and forming the homogenous composite powdered structure. For the preparation of the composite, vacuum impregnation method is used. The particle size distribution accessed by the laser diffraction apparatus proves that incorporation of the organic phase change material into the structure of inorganic siliceous pozzolana does not lead to the clustering of the particles. The compatibility of the prepared composite is characterized by the Fourier transformation infrared analysis (FTIR). Performed DSC analysis shows potential of the developed composite for thermal energy storage that can be easily incorporated into the cement-based matrix of building materials. Based on the obtained results, application of the developed phase change composite can be considered with a great promise.

  15. Development of seasonal heat storage based on stable supercooling of a sodium acetate water mixture

    DEFF Research Database (Denmark)

    Furbo, Simon; Fan, Jianhua; Andersen, Elsa

    2012-01-01

    to and from the sodium acetate water mixture in the modules. By means of the experiments: • The heat exchange capacity rates to and from the sodium acetate water mixture in the heat storage modules were determined for different volume flow rates. • The heat content of the heat storage modules were determined...

  16. Wind power integration with heat pumps, heat storages, and electric vehicles – Energy systems analysis and modelling

    DEFF Research Database (Denmark)

    Hedegaard, Karsten

    in an energy system context. Energy systems analyses reveal that the heat pumps can even without flexible operation contribute significantly to facilitating larger wind power investments and reducing system costs, fuel consumption, and CO2 emissions. When equipping the heat pumps with heat storages, only......The fluctuating and only partly predictable nature of wind challenges an effective integration of large wind power penetrations. This PhD thesis investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing...... research, main focus is put on individual heat pumps in the residential sector and the possibilities for flexible operation, using the heat storage options available. Extensive model development is performed that significantly improves the possibilities for analysing individual heat pumps and heat storages...

  17. Heat Modeling and Material Development of Mg-Based Nanomaterials Combined with Solid Oxide Fuel Cell for Stationary Energy Storage

    Directory of Open Access Journals (Sweden)

    Huaiyu Shao

    2017-11-01

    Full Text Available Mg-based materials have been investigated as hydrogen storage materials, especially for possible onboard storage in fuel cell vehicles for decades. Recently, with the development of large-scale fuel cell technologies, the development of Mg-based materials as stationary storage to supply hydrogen to fuel-cell components and provide electricity and heat is becoming increasingly promising. In this work, numerical analysis of heat balance management for stationary solid oxide fuel cell (SOFC systems combined with MgH2 materials based on a carbon-neutral design concept was performed. Waste heat from the SOFC is supplied to hydrogen desorption as endothermic heat for the MgH2 materials. The net efficiency of this model achieves 82% lower heating value (LHV, and the efficiency of electrical power output becomes 68.6% in minimizing heat output per total energy output when all available heat of waste gas and system is supplied to warm up the storage. For the development of Mg-based hydrogen storage materials, various nano-processing techniques have been widely applied to synthesize Mg-based materials with small particle and crystallite sizes, resulting in good hydrogen storage kinetics, but poor thermal conductivity. Here, three kinds of Mg-based materials were investigated and compared: 325 mesh Mg powers, 300 nm Mg nanoparticles synthesized by hydrogen plasma metal reaction, and Mg50Co50 metastable alloy with body-centered cubic structure. Based on the overall performances of hydrogen capacity, absorption kinetics and thermal conductivity of the materials, the Mg nanoparticle sample by plasma synthesis is the most promising material for this potential application. The findings in this paper may shed light on a new energy conversion and utilization technology on MgH2-SOFC combined concept.

  18. Integrated Combined Heat and Power System Dispatch Considering Electrical and Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Rongxiang Yuan

    2016-06-01

    Full Text Available Wind power has achieved great development in Northern China, but abundant wind power is dissipated, rather than utilized, due to inflexible electricity production of combined heat and power (CHP units. In this paper, an integrated CHP system consisting of CHP units, wind power plants, and condensing power plants is investigated to decouple the power and heat production on both the power supply side and heat supply side, by incorporating electrical energy storage (EES and thermal energy storage (TES. Then the integrated CHP system dispatch (ICHPSD model is formulated to reach the target of reducing wind power curtailment and primary energy consumption. Finally, the feasibility and effectiveness of the proposed ICHPSD model are verified by the six-bus system, and the simulation results show that EES has a better effect on wind power integration than TES. The annual net benefits by incorporating EES and TES increase with increasing wind penetration, but they gradually approach saturation. Introducing both EES and TES can largely increase the amount of wind power integration and improve the operation efficiency of the system.

  19. Active heat exchange system development for latent heat thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Alario, J.; Kosson, R.; Haslett, R.

    1980-01-01

    The selection and evaluation phase of a program to develop active heat exchange concepts for latent heat thermal energy storage systems applicable to the utility industry is described. An evaluation of suitable storage media with melting points in the temperature range of interest (250 to 400/sup 0/C) limited the candidates to molten salts from the chloride, hydroxide and nitrate families, based on high storage capacity, good corrosion characteristics and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24.5NaCl-55.0MgCl/sub 2/% by wt), with a nominal melting point of 385/sup 0/C. Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application (300 MW/sub t/ storage for 6 hours). Two concepts were selected for hardware development: a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. In addition to improving performance by providing a nearly constant heat transfer rate during discharge, these active heat exchanger concepts were estimated to cost at least 25% less than the passive tube-shell design.

  20. Active heat exchange: System development for latent heat thermal energy storage

    Science.gov (United States)

    Alario, J.; Haslett, R.

    1981-03-01

    An active heat exchange method in a latent heat (salt) thermal energy storage system that prevents a low conductivity solid salt layer from forming on heat transfer surfaces was developed. An evaluation of suitable media with melting points in the temperature range of interest (250 to 400 C) limited the candidates to molten salts from the chloride, hydroxide, and nitrate families, based on high storage capacity, good corrosion characteristics, and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a choride eutectic (20.5KCl, 24.5NaCl, 55.0MgCl2 percent by wt.), with a nominal melting point of 385 C.

  1. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    Directory of Open Access Journals (Sweden)

    Borislav Bogdanović

    2009-01-01

    Full Text Available For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

  2. Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for Concentrating Solar Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, Anoop [Terrafore Inc.

    2013-08-14

    A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing the commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during

  3. Thermal energy storage for industrial waste heat recovery

    Science.gov (United States)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    The potential is examined for waste heat recovery and reuse through thermal energy storage in five specific industrial categories: (1) primary aluminum, (2) cement, (3) food processing, (4) paper and pulp, and (5) iron and steel. Preliminary results from Phase 1 feasibility studies suggest energy savings through fossil fuel displacement approaching 0.1 quad/yr in the 1985 period. Early implementation of recovery technologies with minimal development appears likely in the food processing and paper and pulp industries; development of the other three categories, though equally desirable, will probably require a greater investment in time and dollars.

  4. Nanoparticles for heat transfer and thermal energy storage

    Science.gov (United States)

    Singh, Dileep; Cingarapu, Sreeram; Timofeeva, Elena V.; Moravek, Michael

    2015-07-14

    An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

  5. Numerical Computation of Net Radiative Heat Transfer within a Non Absorbing Furnace Enclosure

    Directory of Open Access Journals (Sweden)

    Shuaibu Ndache MOHAMMED

    2006-07-01

    Full Text Available The numerical evaluation of the net radiative heat transfer rate in a single zone, non absorbing furnace enclosure is reported. In this analysis, simplified mathematical furnace model namely, the long furnace model is used to determine furnace performance. The formulation assumes some known temperature values. Thus, heat transfer equations were set up and solved numerically. A FORTRAN computer program was developed and debugged. Results obtained from this study compare favourably well with the results from the traditional graphical method. Also, the computer program developed can handle variations in furnace operating conditions, temperatures, thermal properties and dimensions.

  6. Investigation of methods to transfer heat from solar liquid-heating collectors to heat storage tanks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Horel, J. D.; de Winter, F.

    1978-04-20

    A study was made of the methods available to transfer heat from the collector to the water storage tank in water heating systems. In counterflow heat exchangers used in double loop water heating systems, it was found to be more important to use a high water flowrate than a high heat transfer fluid flowrate. It was earlier thought to be best to have matched WC/sub p/ (mass flowrate-specific heat) products in the loops. It was shown in this study that the water WC/sub p/ product should be about twice as large as that of the heat transfer fluid. It was found that neither the heat exchanger type nor the size was very critical, so that very simple criteria were adequate in determining optimum heat exchanger size. It was found that there is a definite system size below which one should use a traced tank or a coil in a tank. Equations and optimization criteria were developed for traced tanks or tanks with coils. At present, there is no quantitative understanding of liquid to liquid (direct contact) heat exchangers, though they are clearly quite effective. Draindown systems are discussed, and several appendices are included on heat transfer and other characteristics of fluid and of equipment.

  7. Development of Latent Heat Storage Phase Change Material Containing Plaster

    Directory of Open Access Journals (Sweden)

    Diana BAJARE

    2016-05-01

    Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

  8. Excess heat production of future net zero energy buildings within district heating areas in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    2012-01-01

    buildings in Denmark are connected to electricity grids and around half are connected to districtheating (DH) systems. Connecting buildings to larger energy systems enables them to send and receive energy from these systems. This paper’s objective is to examine how excess heat production from NZEBs...... excess heat production from solar thermal collectors. The main findings are that the excess heat from NZEBs can benefit DH systems by decreasing the production from production units utilizing combustible fuels. In DH areas where the heat demand in summer months is already covered by renewable energy......Denmark’s long-term energy goal is to develop an energy system solely based on renewable energy sources by 2050. To reach this goal, energy savings in buildings is essential. Therefore, the focus on energy efficient measures in buildings and netzeroenergybuildings (NZEBs) has increased. Most...

  9. Experimental determination of soil heat storage for the simulation of heat transport in a coastal wetland

    Science.gov (United States)

    Swain, Michael; Swain, Matthew; Lohmann, Melinda; Swain, Eric

    2012-01-01

    Two physical experiments were developed to better define the thermal interaction of wetland water and the underlying soil layer. This information is important to numerical models of flow and heat transport that have been developed to support biological studies in the South Florida coastal wetland areas. The experimental apparatus consists of two 1.32. m diameter by 0.99. m tall, trailer-mounted, well-insulated tanks filled with soil and water. A peat-sand-soil mixture was used to represent the wetland soil, and artificial plants were used as a surrogate for emergent wetland vegetation based on size and density observed in the field. The tanks are instrumented with thermocouples to measure vertical and horizontal temperature variations and were placed in an outdoor environment subject to solar radiation, wind, and other factors affecting the heat transfer. Instruments also measure solar radiation, relative humidity, and wind speed.Tests indicate that heat transfer through the sides and bottoms of the tanks is negligible, so the experiments represent vertical heat transfer effects only. The temperature fluctuations measured in the vertical profile through the soil and water are used to calibrate a one-dimensional heat-transport model. The model was used to calculate the thermal conductivity of the soil. Additionally, the model was used to calculate the total heat stored in the soil. This information was then used in a lumped parameter model to calculate an effective depth of soil which provides the appropriate heat storage to be combined with the heat storage in the water column. An effective depth, in the model, of 5.1. cm of wetland soil represents the heat storage needed to match the data taken in the tank containing 55.9. cm of peat/sand/soil mix. The artificial low-density laboratory sawgrass reduced the solar energy absorbed by the 35.6. cm of water and 55.9. cm of soil at midday by less than 5%. The maximum heat transfer into the underlying peat-sand-soil mix

  10. Heat of Fusion Storage with High Solar Fraction for Solar Low Energy Buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2006-01-01

    of the storage to cool down below the melting point without solidification preserving the heat of fusion energy. If the supercooled storage reaches the surrounding temperature no heat loss will take place until the supercooled salt is activated. The investigation shows that this concept makes it possible...... to achieve 100% coverage of space heating and domestic hot water in a low energy house in a Danish climate with a solar heating system with 36 m² flat plate solar collector and approximately 10 m³ storage with sodium acetate. A traditional water storage solution aiming at 100% coverage will require a storage......This paper presents the theoretical investigation on a concept for a seasonal thermal storage based on the phase change material sodium acetate trihydrate with active use of supercooling as a measure to achieve a partly heat loss free thermal storage. The effect of supercooling allows a melted part...

  11. Heat of Fusion Storage with High Solar Fraction for Solar Low Energy Buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    The paper presents the results of a theoretical investigation of use of phase change materials (PCM’s) with active use of super cooling as a measure for obtaining partly heat loss free seasonal storages for solar combi-systems with 100% coverage of the energy demand of both space heating...... storage parts already melted to cool down to surrounding temperature without solidification in which state that part of the storage will be heat loss free but still will hold the latent heat in form of the heat of fusion. At the time of energy demand the solidification of the super-cooled storage part...... and domestic hot water. The work is part of the IEA Solar Heating & Cooling Programme Task 32 “Advanced Storage Concepts for Solar Buildings”. The investigations are based on a newly developed TRNSYS type for simulation of a PCM-storage with controlled super-cooling. The super-cooling makes it possible to let...

  12. Castor-1C spent fuel storage cask decay heat, heat transfer, and shielding analyses

    Energy Technology Data Exchange (ETDEWEB)

    Rector, D.R.; McCann, R.A.; Jenquin, U.P.; Heeb, C.M.; Creer, J.M.; Wheeler, C.L.

    1986-12-01

    This report documents the decay heat, heat transfer, and shielding analyses of the Gesellschaft fuer Nuklear Services (GNS) CASTOR-1C cask used in a spent fuel storage demonstration performed at Preussen Elektra's Wurgassen nuclear power plant. The demonstration was performed between March 1982 and January 1984, and resulted in cask and fuel temperature data and cask exterior surface gamma-ray and neutron radiation dose rate measurements. The purpose of the analyses reported here was to evaluate decay heat, heat transfer, and shielding computer codes. The analyses consisted of (1) performing pre-look predictions (predictions performed before the analysts were provided the test data), (2) comparing ORIGEN2 (decay heat), COBRA-SFS and HYDRA (heat transfer), and QAD and DOT (shielding) results to data, and (3) performing post-test analyses if appropriate. Even though two heat transfer codes were used to predict CASTOR-1C cask test data, no attempt was made to compare the two codes. The codes are being evaluated with other test data (single-assembly data and other cask data), and to compare the codes based on one set of data may be premature and lead to erroneous conclusions.

  13. Effects of preincubation heating of broiler hatching eggs during storage, flock age, and length of storage period on hatchability.

    Science.gov (United States)

    Gucbilmez, M; Ozlü, S; Shiranjang, R; Elibol, O; Brake, J

    2013-12-01

    The effects of heating of eggs during storage, broiler breeder age, and length of egg storage on hatchability of fertile eggs were examined in this study. Eggs were collected from Ross 344 male × Ross 308 broiler breeders on paper flats, held overnight (1 d) at 18°C and 75% RH, and then transferred to plastic trays. In experiment 1, eggs were obtained at 28, 38, and 53 wk of flock age. During a further 10 d of storage, eggs either remained in the storage room (control) or were subjected to a heat treatment regimen of 26°C for 2 h, 37.8°C for 3 h, and 26°C for 2 h in a setter at d 5 of storage. In experiment 2, eggs from a flock at 28 wk of age were heated for 1 d of a 6-d storage period. Eggs from a 29-wk-old flock were either heated at d 1 or 5 of an 11-d storage period in experiment 3. In experiment 4, 27-wk-old flock eggs were heated twice at d 1 and 5 of an 11-d storage period. Control eggs stored for 6 or 11 d were coincubated as appropriate in each experiment. Heating eggs at d 5 of an 11-d storage period increased hatchability in experiment 1. Although no benefit of heating 28-wk-old flock eggs during 6 d of storage in experiment 2 was observed, heating eggs from a 29-wk-old flock at d 1 or 5 of an 11-d storage period increased hatchability in experiment 3. Further, heating eggs from a 27-wk-old flock twice during 11 d of storage increased hatchability in experiment 4. These effects were probably due to the fact that eggs from younger flocks had been reported to have many embryos at a stage of development where the hypoblast had not yet fully developed (less than EG-K12 to EG-K13), such that heating during extended storage advanced these embryos to a more resistant stage.

  14. Thermo-mechanics in packed beds: Modeling and design of high temperature heat storage

    OpenAIRE

    Dreißigacker, Volker

    2015-01-01

    Several novel power plant technologies, such as concentrating solar power (CSP) plants or adiabatic compressed air storage (ACAES), depend on heat storage systems as a central plant element. Where gaseous heat transfer media at elevated temperature levels are used, a regenerator-type heat storage is a particularly cost-effective solution. A large-scale design based on a packed bed inventory can further reduce investment costs, but is fraught with the risk of mechanical failures caused by the ...

  15. Elevated CO2 maintains grassland net carbon uptake under a future heat and drought extreme.

    Science.gov (United States)

    Roy, Jacques; Picon-Cochard, Catherine; Augusti, Angela; Benot, Marie-Lise; Thiery, Lionel; Darsonville, Olivier; Landais, Damien; Piel, Clément; Defossez, Marc; Devidal, Sébastien; Escape, Christophe; Ravel, Olivier; Fromin, Nathalie; Volaire, Florence; Milcu, Alexandru; Bahn, Michael; Soussana, Jean-François

    2016-05-31

    Extreme climatic events (ECEs) such as droughts and heat waves are predicted to increase in intensity and frequency and impact the terrestrial carbon balance. However, we lack direct experimental evidence of how the net carbon uptake of ecosystems is affected by ECEs under future elevated atmospheric CO2 concentrations (eCO2). Taking advantage of an advanced controlled environment facility for ecosystem research (Ecotron), we simulated eCO2 and extreme cooccurring heat and drought events as projected for the 2050s and analyzed their effects on the ecosystem-level carbon and water fluxes in a C3 grassland. Our results indicate that eCO2 not only slows down the decline of ecosystem carbon uptake during the ECE but also enhances its recovery after the ECE, as mediated by increases of root growth and plant nitrogen uptake induced by the ECE. These findings indicate that, in the predicted near future climate, eCO2 could mitigate the effects of extreme droughts and heat waves on ecosystem net carbon uptake.

  16. Temporal and spatial changes in mixed layer properties and atmospheric net heat flux in the Nordic Seas

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A; Alekseev, G [SI ' Arctic and Antarctic Research Institute' , St. Petersburg (Russian Federation); Korablev, A; Esau, I, E-mail: avsmir@aari.nw.r [Nansen Environmental and Remote Sensing Centre, Bergen (Norway)

    2010-08-15

    The Nordic Seas are an important area of the World Ocean where warm Atlantic waters penetrate far north forming the mild climate of Northern Europe. These waters represent the northern rim of the global thermohaline circulation. Estimates of the relationships between the net heat flux and mixed layer properties in the Nordic Seas are examined. Oceanographic data are derived from the Oceanographic Data Base (ODB) compiled in the Arctic and Antarctic Research Institute. Ocean weather ship 'Mike' (OWS) data are used to calculate radiative and turbulent components of the net heat flux. The net shortwave flux was calculated using a satellite albedo dataset and the EPA model. The net longwave flux was estimated by Southampton Oceanography Centre (SOC) method. Turbulent fluxes at the air-sea interface were calculated using the COARE 3.0 algorithm. The net heat flux was calculated by using oceanographic and meteorological data of the OWS 'Mike'. The mixed layer depth was estimated for the period since 2002 until 2009 by the 'Mike' data as well. A good correlation between these two parameters has been found. Sensible and latent heat fluxes controlled by surface air temperature/sea surface temperature gradient are the main contributors into net heat flux. Significant correlation was found between heat fluxes variations at the OWS 'Mike' location and sea ice export from the Arctic Ocean.

  17. Non-equilibrium thermochemical heat storage in porous media

    DEFF Research Database (Denmark)

    Nagel, T.; Shao, H.; Singh, Ashok

    2013-01-01

    compressible gas flow through a porous solid is presented along with its finite element implementation where solid-gas reactions occur and both phases have individual temperature fields. The model is embedded in the Theory of Porous Media and the derivation is based on the evaluation of the Clausius...... determine reaction kinetics. To advance this technology beyond the laboratory stage requires a thorough theoretical understanding of the multiphysics phenomena and their quantification on a scale relevant to engineering analyses. Here, the theoretical derivation of a macroscopic model for multicomponent......Thermochemical energy storage can play an important role in the establishment of a reliable renewable energy supply and can increase the efficiency of industrial processes. The application of directly permeated reactive beds leads to strongly coupled mass and heat transport processes that also...

  18. Seven Operation Modes and Simulation Models of Solar Heating System with PCM Storage Tank

    Directory of Open Access Journals (Sweden)

    Juan Zhao

    2017-12-01

    Full Text Available A physical model and dynamic simulation models of a solar phase-change heat storage heating system with a plate solar collector, phase-change material (PCM storage tank, plate heat exchanger, and auxiliary heat sources were established. A control strategy and numerical models for each of seven different operation modes that cover the entire heating season of the system were developed for the first time. The seven proposed operation modes are Mode 1: free cooling; Mode 2: reservation of heat absorbed by the solar collector in the PCM storage tank when there is no heating demand; Mode 3: direct supply of the heating demand by the solar collector; Mode 4: use of the heat absorbed by the solar collector to meet the heating demands, with the excess heat stored in the PCM storage tank; Mode 5: use of heat stored in the PCM storage tank to meet the heating demands, Mode 6: combined use of heat stored in the PCM storage tank and the auxiliary heating sources to meet the heating demands; and Mode 7: exclusive use of the auxiliary heat sources in order to meet the heating demands. Mathematical models were established for each of the above seven operation modes, taking into consideration the effects of the outdoor meteorological parameters and terminal load on the heating system. The real-time parameters for the entire heating season of the system with respect to the different operation modes can be obtained by solving the simulation models, and used as reference for the optimal design and operation of the actual system.

  19. Applications of thermal energy storage to waste heat recovery in the food processing industry

    Science.gov (United States)

    Wojnar, F.; Lunberg, W. L.

    1980-01-01

    A study to assess the potential for waste heat recovery in the food industry and to evaluate prospective waste heat recovery system concepts employing thermal energy storage was conducted. The study found that the recovery of waste heat in canning facilities can be performed in significant quantities using systems involving thermal energy storage that are both practical and economical. A demonstration project is proposed to determine actual waste heat recovery costs and benefits and to encourage system implementation by the food industry.

  20. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    OpenAIRE

    Peng Hu; Gao-Wei Zhang; Long-Xiang Chen; Ming-Hou Liu

    2017-01-01

    Electrothermal energy storage (ETES) provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analys...

  1. Performance enhancement of a heat pump system with ice storage subcooler

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Ming-Jer [Department of Electrical Engineering, Nan-Kai University of Technology, No.568 Chung Cheng Road, Tsao Tun, Nan Tou, Taiwan 54243 (China); Kuo, Yu-Fu; Cheng, Chiao-Hung; Chen, Sih-Li [Department of Mechanical Engineering, National Taiwan University, No.1, Sec.4 Roosevelt Road, Taipei, Taiwan 10617 (China); Shen, Chih-Chiu [Department of Mechanical Engineering, National Chung Hsing University, No.250, Kuo Kuang Road, Taichung, Taiwan 40227 (China)

    2010-03-15

    This article experimentally investigates the thermal performance of a heat pump system with an ice storage subcooler. The system supplies heating and cooling demands to two greenhouses with temperature ranging 308{proportional_to}323 K and 273{proportional_to}291 K respectively and utilizes an ice storage tank to subcool the condensed refrigerant, which can enhance the system coefficient of performance (COP). The ice storage tank charges for storing ice, when the cooling load is less than the nominal cooling capacity. While the cooling load is larger than the nominal cooling capacity, the ice storage tank discharges for subcooling. The results show that in the charge mode the heat pump COP of ice storage system is 12% higher than that without ice storage tank. Under the discharge mode, the ice storage system provides the refrigerator COP 15% higher than that without ice storage tank. (author)

  2. Slow heat release - solid fuel stove with acetat-trihydrate heat storage sodium; Slow heat release - Braendeovn med salthydratvarmelager

    Energy Technology Data Exchange (ETDEWEB)

    Zielke, U.; Bjerrum, M.; Noergaard, T. (Teknologisk Institut, Aarhus (Denmark))

    2012-07-01

    Of the 700,000 solid fuel stoves in Denmark, 600,000 are installed in permanent residences, and 100,000 are installed in summer cottages. Recent examinations have shown that in the heating season, these stoves contribute with a not negligible share of air pollution in the cities. The reason is often inexpedient firing and an inappropriate performance of the stove. In many cases the thermal output of the stove exceeds the heating demand of a modern residence; and the user typically reduces the stove's combustion air supply with the purpose of lowering the temperature of the accommodation space. The result is a sooting combustion followed by undesired and environmentally damaging emissions. In worst case the user fires throughout the night reducing the air to an absolutely minimum. In these situations the fuel smoulders all night, and the stove emits large amounts of undesirable and unhealthy emissions. By constructing the stove with a heat storage that can accumulate the heat from the stove and emit the heat later (when not firing), the problem with the unhealthy ''night firings'' should be eliminated. The project started with a pre-examination regarding suitable materials for a heat storage and a literature study of the subject. By using an OGC material, in this case sodiumacetat-trihydrat, the weight of the stove, in spite of the heat storage, could be held within reasonable frames, since 130 kg PCM can contain the same heat amount as 1,200 kg stone. The great challenge was to compensate for PCM's poor heat conductivities, to distribute the heat in the whole heat storage, making it melt regularly without generating local boiling. This problem was solved by construction measures. The system with sodiumacetat-trihydrat, which melts by 58 deg. C, came to function satisfactorily. 14 hours after the last firing, the temperature of the heat storage was 30 deg. C. The tests with PCM were followed by an extensive emission measuring program

  3. Laboratory test of a prototype heat storage module based on stable supercooling of sodium acetate trihydrate

    DEFF Research Database (Denmark)

    Dannemand, Mark; Kong, Weiqiang; Fan, Jianhua

    2015-01-01

    Laboratory test of a long term heat storage module utilizing the principle of stable supercooling of 199.5 kg of sodium acetate water mixture has been carried out. Avoiding phase separation of the incongruently melting salt hydrate by using the extra water principle increased the heat storage...

  4. Design and fabrication of a direct contact latent thermal energy storage heat exchanger

    Science.gov (United States)

    Alario, J. P.; Brown, R. F.

    1984-06-01

    Originally intended for solar-thermal applications, the present direct contact, latent thermal energy storage heat exchanger has a 10 kW-h storage capacity and a 10 kW heat transfer rate. The inorganic eutectic NaNO3-KNO3 salt is used as the latent energy storage medium, and the liquid metal Pb-Bi eutectic is used as an intermediate heat exchange fluid. The heat exchange mechanism injects molten salt droplets at the bottom of a counterflowing liquid metal column.

  5. An investigation of the storage capability of district heating networks. Consequences of heat production; Untersuchung der Speicherfaehigkeit von Fernwaermenetzen. Auswirkungen auf die Waermeerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Sebastian; Felsmann, Clemens [Technische Univ. Dresden (Germany). Professur fuer Gebaeudeenergietechnik und Waermeversorgung

    2012-01-15

    The storage of energy is a key issue in terms of the energy policy turnaround and the concomitant increase in decentralized power generation. District heating networks can be used as a heat storage. But is this reasonable energetically and economically? And what is the situation with the storage capacity of district heating networks? How does this storage capability impact on the use of heat sources? The authors of the contribution under consideration try to give an answer to these questions.

  6. Active heat exchange system development for latent heat thermal energy storage

    Science.gov (United States)

    Alario, J.; Kosson, R.; Haslett, R.

    1980-01-01

    Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application (300 MW sub t storage for 6 hours). Two concepts were selected for hardware development: (1) a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and (2) a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which was nickel plated to decrease adhesion forces. In addition to improving performance by providing a nearly constant transfer rate during discharge, these active heat exchanger concepts were estimated to cost at least 25% less than the passive tube-shell design.

  7. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    Science.gov (United States)

    Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

    1977-01-01

    The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only 60% to 80% of peak load. As peak load increases, the present practice is to purchase power from other grid facilities or to bring older less efficient fossil-fuel plants on line which increase the cost of electric power. The widespread use of oil-fired boilers, gas turbine and diesel equipment to meet peaking loads depletes our oil-based energy resources. Heat exchangers utilizing molten salts can be used to level the energy consumption curve. The study begins with a demand analysis and the consideration of several existing modern fossil-fuel and nuclear power plants for use as models. Salts are evaluated for thermodynamic, economic, corrosive, and safety characteristics. Heat exchanger concepts are explored and heat exchanger designs are conceived. Finally, the economics of TES conversions in existing plants and new construction is analyzed. The study concluded that TES is feasible in electric power generation. Substantial data are presented for TES design, and reference material for further investigation of techniques is included.

  8. Thermochemical Energy Storage for Process Waste Heat: Simulation and Model Validaton

    OpenAIRE

    Molenda, Margarethe; Bouché , Martin; Linder, Marc; Wörner, Antje

    2012-01-01

    Thermochemical energy storage is based on the application of reversible chemical reactions for storage of thermal energy. Gas-solid reactions are well suited due to easily separable products and high reaction enthalpies resulting in high storage densities. In addition, heat transformation processes can be realized with this energy storage technology. The reaction temperature can be adjusted by variation of the partial pressure of the gaseous component resulting in discharging temperatures bei...

  9. Microscale Enhancement of Heat and Mass Transfer for Hydrogen Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Drost, Kevin [Oregon State Univ., Corvallis, OR (United States); Jovanovic, Goran [Oregon State Univ., Corvallis, OR (United States); Paul, Brian [Oregon State Univ., Corvallis, OR (United States)

    2015-09-30

    The document summarized the technical progress associated with OSU’s involvement in the Hydrogen Storage Engineering Center of Excellence. OSU focused on the development of microscale enhancement technologies for improving heat and mass transfer in automotive hydrogen storage systems. OSU’s key contributions included the development of an extremely compact microchannel combustion system for discharging hydrogen storage systems and a thermal management system for adsorption based hydrogen storage using microchannel cooling (the Modular Adsorption Tank Insert or MATI).

  10. Heat pump water heater and storage tank assembly

    Science.gov (United States)

    Dieckmann, John T.; Nowicki, Brian J.; Teagan, W. Peter; Zogg, Robert

    1999-09-07

    A water heater and storage tank assembly comprises a housing defining a chamber, an inlet for admitting cold water to the chamber, and an outlet for permitting flow of hot water from the chamber. A compressor is mounted on the housing and is removed from the chamber. A condenser comprises a tube adapted to receive refrigerant from the compressor, and winding around the chamber to impart heat to water in the chamber. An evaporator is mounted on the housing and removed from the chamber, the evaporator being adapted to receive refrigerant from the condenser and to discharge refrigerant to conduits in communication with the compressor. An electric resistance element extends into the chamber, and a thermostat is disposed in the chamber and is operative to sense water temperature and to actuate the resistance element upon the water temperature dropping to a selected level. The assembly includes a first connection at an external end of the inlet, a second connection at an external end of the outlet, and a third connection for connecting the resistance element, compressor and evaporator to an electrical power source.

  11. Experimental testing of various heat transfer structures in a flat plate thermal energy storage unit

    Science.gov (United States)

    Johnson, Maike; Fiß, Michael; Klemm, Torsten

    2016-05-01

    For solar process heat applications with steam as the working fluid and varying application parameters, a novel latent heat storage concept has been developed using an adaptation of a flat plate heat exchanger as the storage concept. Since the pressure level in these applications usually does not exceed 30 bar, an adaptation with storage material chambers arranged between heat transfer medium chambers is possible. Phase change materials are used as the storage medium, so that the isothermal evaporation of steam during discharging of the storage is paired with the isothermal solidification of the storage material. Heat transfer structures can be inserted into the chambers to adjust the power level for a given application. By combining the required number of flat plate heat exchanger compartments and inserting the appropriate heat transfer structure, the design can easily be adjusted for the required power level and capacity for a specific application. Within this work, the technical feasibility of this concept is proven. The dependence of the operating characteristics on the geometry of the heat exchanger is identified. A focus is on varying the power density by integrating conductive heat structures in the PCM.

  12. Experimental and numerical investigation of a scalable modular geothermal heat storage system

    Science.gov (United States)

    Nordbeck, Johannes; Bauer, Sebastian; Beyer, Christof

    2017-04-01

    Storage of heat will play a significant role in the transition towards a reliable and renewable power supply, as it offers a way to store energy from fluctuating and weather dependent energy sources like solar or wind power and thus better meet consumer demands. The focus of this study is the simulation-based design of a heat storage system, featuring a scalable and modular setup that can be integrated with new as well as existing buildings. For this, the system can be either installed in a cellar or directly in the ground. Heat supply is by solar collectors, and heat storage is intended at temperatures up to about 90°C, which requires a verification of the methods used for numerical simulation of such systems. One module of the heat storage system consists of a helical heat exchanger in a fully water saturated, high porosity cement matrix, which represents the heat storage medium. A lab-scale storage prototype of 1 m3 volume was set up in a thermally insulated cylinder equipped with temperature and moisture sensors as well as flux meters and temperature sensors at the inlet and outlet pipes in order to experimentally analyze the performance of the storage system. Furthermore, the experimental data was used to validate an accurate and spatially detailed high-resolution 3D numerical model of heat and fluid flow, which was developed for system design optimization with respect to storage efficiency and environmental impacts. Three experiments conducted so far are reported and analyzed in this work. The first experiment, consisting of cooling of the fully loaded heat storage by heat loss across the insulation, is designed to determine the heat loss and the insulation parameters, i.e. heat conductivity and heat capacity of the insulation, via inverse modelling of the cooling period. The average cooling rate experimentally found is 1.2 °C per day. The second experiment consisted of six days of thermal loading up to a storage temperature of 60°C followed by four days

  13. Impact of elevated carbon dioxide on soil heat storage and heat flux under unheated low-tunnels conditions.

    Science.gov (United States)

    Al-Kayssi, A W; Mustafa, S H

    2016-11-01

    Suboptimal regimes of air and soil temperature usually occur under unheated low-tunnels during winter crop cycles. CO2 is one of the most important gases linked to climate change and posing challenge to the current agricultural productivity. Field experiment was conducted in unheated low-tunnels (10.0 m long, 1.5 m wide and 1.0 m high) during winter and spring periods to evaluate the increasing CO2 concentration (352, 709, 1063, 1407, and 1761 ppm) on net radiation budget, soil-air thermal regime and pepper plants growth development and yield. CO2 was injected into each hollow space of the tunnel double-layer transparent polyethylene covers. Recorded integral net longwave radiation increased from 524.81 to 1111.84 Wm(-2) on January when CO2 concentration increased from 352 to 1761 ppm. A similar trend was recorded on February. Moreover, minimum soil surface and air temperatures were markedly increased from -1.3 and -6.8 °C to 3.4 and 0.6 °C, when CO2 concentration increased from 352 to 1761 ppm. Additionally, soil heat flux as well as soil heat storage increased with increasing CO2 concentrations accordingly. Increasing the tunnel minimum air and soil temperatures with the CO2 concentration treatments 1063, 1407 and 1761 ppm reflected in a significant pepper yield (3.19, 5.06 and 6.13 kg m(-2)) due to the modification of the surrounding plants microenvironment and prevented pepper plants from freezing and the accelerated the plant growth. On the contrary, the drop of minimum air and soil temperatures to freezing levels with the CO2 concentration treatments 352 and 709 ppm resulted in the deterioration of pepper plants development during the early growth stages on January. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Thermochemical Storage of Middle Temperature Wasted Heat by Functionalized C/Mg(OH2 Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Emanuela Mastronardo

    2017-01-01

    Full Text Available For the thermochemical performance implementation of Mg(OH2 as a heat storage medium, several hybrid materials have been investigated. For this study, high-performance hybrid materials have been developed by exploiting the authors’ previous findings. Expanded graphite (EG/carbon nanotubes (CNTs-Mg(OH2 hybrid materials have been prepared through Mg(OH2 deposition-precipitation over functionalized, i.e., oxidized, or un-functionalized EG or CNTs. The heat storage performances of the carbon-based hybrid materials have been investigated through a laboratory-scale experimental simulation of the heat storage/release cycles, carried out by a thermogravimetric apparatus. This study offers a critical evaluation of the thermochemical performances of developed materials through their comparison in terms of heat storage and output capacities per mass and volume unit. It was demonstrated that both EG and CNTs improves the thermochemical performances of the storage medium in terms of reaction rate and conversion with respect to pure Mg(OH2. With functionalized EG/CNTs-Mg(OH2, (i the potential heat storage and output capacities per mass unit of Mg(OH2 have been completely exploited; and (ii higher heat storage and output capacities per volume unit were obtained. That means, for technological applications, as smaller volume at equal stored/released heat.

  15. Quantification of the reactions in heat storage systems in the Malm aquifer

    Science.gov (United States)

    Ueckert, Martina; Baumann, Thomas

    2017-04-01

    Combined heat and power plants (CHP) are efficient and environmentally friendly because excess heat produced during power generation is used for heating purposes. While the power demand remains rather constant throughout the year, the heat demand shows seasonal variations. In a worst-case scenario, the heat production in winter is not sufficient, and the power production in summer has to be ramped down because the excess heat cannot be released to the environment. Therefore, storage of excess heat of CHP is highly beneficial from an economic and an ecological point of view. Aquifer thermal energy storage (ATES) is considered as a promising technology for energy storage. In a typical setting, water from an aquifer is produced, heated up by excess heat from the CHP and injected through a second borehole back into the aquifer. The carbonate rocks of the upper Jurrasic in the Molasse Basin seem to be promising sites for aquifer heat storage because of their high transmissivity combined with a typical geological setting with tight caprock. However, reactions in the aquifer cannot be neglected and may become the limiting process of the whole operation. While there have been several studies performed in clastic aquifers and for temperatures below 100°C, the knowledge about high injection temperatures and storage into a carbonatic aquifer matrix is still limited. Within a research project funded by the Bavarian State Ministry for Economic Affairs and the BMW Group, the storage and recuperation of excess heat energy into the Bavarian Malm aquifer with flow rates of 15 L/s and temperatures of up to 110°C was investigated. The addition of {CO_2} was used to prevent precipitations. Data from the field site was backed up by autoclave experiments and used to verify a conceptional hydrogeochemical model with PhreeqC for the heat storage operation. The model allows to parametrize the operation and to predict possible reactions in the aquifer.

  16. Energy Optimization for Transcritical CO2 Heat Pump for Combined Heating and Cooling and Thermal Storage Applications

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Blarke, Morten; Yazawa, Kazuaki

    2012-01-01

    and cold thermal storages know as Thermal Battery (TB) (Blarke, 2012). Smart and effective use of intermittent renewable energy resources (for example solar and wind power) is obtained supplying water heating (>70 oC) and cooling services (...A transcritical heat pump (THP) cycle using carbon dioxide (CO2) as the refrigerant is known to feature an excellent coefficient of performance (COP) as a thermodynamic system. Using this feature, we are designing and building a system that combines a water-to-water CO2 heat pump with both hot...... hypothesis is that if electricity generated by intermittent sources is destined for thermal end-uses an efficient conversion of electricity to thermal energy and storage enables a flexible power supply. Thermal storage is more cost-effective than any electro-chemical or mechanical storage technology...

  17. Active heat exchange system development for latent heat thermal energy storage

    Science.gov (United States)

    Alario, J.; Haslett, R.

    1980-03-01

    Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application. Two concepts selected for hardware development are a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. Suitable phase change material (PCM) storage media with melting points in the temperature range of interest (250 C to 400 C) were investigated. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24/5 NaCl-55.0MgCl 2% by wt.), with a nominal melting point of 385 C.

  18. On energy optimisation in multipurpose batch plants using heat storage

    CSIR Research Space (South Africa)

    Majozi, T

    2010-10-01

    Full Text Available The use of heat integration in multipurpose batch plants to minimise energy usage has been in the literature for more than two decades. Direct heat integration may be exploited when the heat source and heat sink processes are active over a common...

  19. Initial Development of a Combined PCM and TABS Solution for Heat Storage and Cooling

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2011-01-01

    heat storage capacity. A series of simulations were conducted using the COMSOL program to obtain knowledge regarding the dynamic heat storage capacity of the investigated hollow core deck element as a function of the amount and location of PCM. Furthermore, the dynamic heat storage capacity...... of a passive deck element and the possible cooling power of the thermally activated deck element were predicted and then compared. Finally, results obtained from precise numerical simulations in COMSOL Multiphysics were compared with results calculated in the whole building simulation software BSim. Initial...

  20. Heat storage rate and acute fatigue in rats

    Directory of Open Access Journals (Sweden)

    L.O.C. Rodrigues

    2003-01-01

    Full Text Available Thermal environmental stress can anticipate acute fatigue during exercise at a fixed intensity (%VO2max. Controversy exists about whether this anticipation is caused by the absolute internal temperature (Tint, ºC, by the heat storage rate (HSR, cal/min or by both mechanisms. The aim of the present study was to study acute fatigue (total exercise time, TET during thermal stress by determining Tint and HSR from abdominal temperature. Thermal environmental stress was controlled in an environmental chamber and determined as wet bulb globe temperature (ºC, with three environmental temperatures being studied: cold (18ºC, thermoneutral (23.1ºC or hot (29.4ºC. Six untrained male Wistar rats weighing 260-360 g were used. The animals were submitted to exercise at the same time of day in the three environments and at two treadmill velocities (21 and 24 m/min until exhaustion. After implantation of a temperature sensor and treadmill adaptation, the animals were submitted to a Latin square experimental design using a 2 x 3 factorial scheme (velocity and environment, with the level of significance set at P<0.05. The results showed that the higher the velocity and the ambient temperature, the lower was the TET, with these two factors being independent. This result indicated that fatigue was independently affected by both the increase in exercise intensity and the thermal environmental stress. Fatigue developed at different Tint and HSR showed the best inverse relationship with TET. We conclude that HSR was the main anticipating factor of fatigue.

  1. Energy-Saving Analysis of Solar Heating System with PCM Storage Tank

    Directory of Open Access Journals (Sweden)

    Juan Zhao

    2018-01-01

    Full Text Available A solar heating system (SHS with a phase change material (PCM thermal storage tank is proposed with the view that traditional heat water storage tanks present several problems including large space requirements, significant heat loss and unstable system performance. An entire heating season (November–March is selected as the research period on the basis of numerical models of the SHS-PCM. In addition, taking a public building in Lhasa as the object, the heating conditions, contribution rate of solar energy, and overall energy-saving capability provided by the heating system are analyzed under different PCM storage tanks and different terminal forms. The results show that an SHS with a PCM tank provides a 34% increase in energy saving capability compared to an ordinary water tank heating system. It is suggested that the design selection parameters of the PCM storage tank should specify a daily heat storage capacity that satisfies 70~80% of the entire heating season. A floor radiant system with supply/return water temperatures of 40/35 °C provides the optimal operation and the largest energy saving capability.

  2. Numerical Heat Transfer Studies of a Latent Heat Storage System Containing Nano-Enhanced Phase Change Material

    Directory of Open Access Journals (Sweden)

    S F Hosseinizadeh

    2011-01-01

    Full Text Available The heat transfer enhancement in the latent heat thermal energy storage system through dispersion of nanoparticle is reported. The resulting nanoparticle-enhanced phase change materials (NEPCM exhibit enhanced thermal conductivity in comparison to the base material. The effects of nanoparticle volume fraction and some other parameters such as natural convection are studied in terms of solid fraction and the shape of the solid-liquid phase front. It has been found that higher nanoparticle volume fraction result in a larger solid fraction. The present results illustrate that the suspended nanoparticles substantially increase the heat transfer rate and also the nanofluid heat transfer rate increases with an increase in the nanoparticles volume fraction. The increase of the heat release rate of the NEPCM shows its great potential for diverse thermal energy storage application.

  3. Solar powered absorption cycle heat pump using phase change materials for energy storage

    Science.gov (United States)

    Middleton, R. L.

    1972-01-01

    Solar powered heating and cooling system with possible application to residential homes is described. Operating principles of system are defined and illustration of typical energy storage and exchange system is provided.

  4. Heating and cooling system for an on-board gas adsorbent storage vessel

    Energy Technology Data Exchange (ETDEWEB)

    Tamburello, David A.; Anton, Donald L.; Hardy, Bruce J.; Corgnale, Claudio

    2017-06-20

    In one aspect, a system for controlling the temperature within a gas adsorbent storage vessel of a vehicle may include an air conditioning system forming a continuous flow loop of heat exchange fluid that is cycled between a heated flow and a cooled flow. The system may also include at least one fluid by-pass line extending at least partially within the gas adsorbent storage vessel. The fluid by-pass line(s) may be configured to receive a by-pass flow including at least a portion of the heated flow or the cooled flow of the heat exchange fluid at one or more input locations and expel the by-pass flow back into the continuous flow loop at one or more output locations, wherein the by-pass flow is directed through the gas adsorbent storage vessel via the by-pass line(s) so as to adjust an internal temperature within the gas adsorbent storage vessel.

  5. Thermal performance and heat transport in aquifer thermal energy storage

    NARCIS (Netherlands)

    Sommer, W.T.; Doornenbal, P.J.; Drijver, B.C.; Gaans, van P.F.M.; Leusbrock, I.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    Aquifer thermal energy storage (ATES) is used for seasonal storage of large quantities of thermal energy. Due to the increasing demand for sustainable energy, the number of ATES systems has increased rapidly, which has raised questions on the effect of ATES systems on their surroundings as well as

  6. Potential benefits of thermal energy storage in the proposed Twin Cities district heating-cogeneration system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.F.

    1979-10-01

    A new, large, cogeneration-district heating system has been proposed for the Twin Cities area, using hot water in a closed-loop system. The proposed system, as described by Studsvik Energiteknik AB of Sweden, does not employ thermal energy storage (TES). Four cases have been developed, describing system configurations which would employ TES, to evaluate the potential benefits of incorporating annual-cycle TES into the Twin Cities system. The potential benefits are found to be substantial, confirming results of earlier, generic studies of aquifer TES. The reference (Studsvik) system employs oil-fired boilers to supplement cogenerated heat, for handling peak loads and providing standby reserve. TES can serve the same function, with net energy savings in spite of heat losses during storage, by making it possible to operate the cogeneration equipment at higher capacity factors. Coal replaces oil as the fuel consumed. Energy savings of the reference system are impressive; energy savings with TES are 2 to 22% better. Capital cost requirements for boilers, cogeneration equipment, and pipelines are reduced by $66 to $258 million. The breakeven capital cost of TES is estimated to range from $43 to $76 per kilowatt peak thermal input to or withdrawal from aquifer TES. A factor in evaluating the breakeven operating cost of TES is the $14 to $31 million per year saving in cost of fuel. Abatement of air pollution and thermal pollution are concomitant benefits.

  7. Modelling the Size of Seasonal Thermal Storage in the Solar District Heating System

    Directory of Open Access Journals (Sweden)

    Giedrė Streckienė

    2012-12-01

    Full Text Available The integration of a thermal storage system into the solar heating system enables to increase the use of solar thermal energy in buildings and allows avoiding the mismatch between consumers’ demand and heat production in time. The paper presents modelling a seasonal thermal storage tank various sizes of which have been analyzed in the district solar heating system that could cover a part of heat demand for the district of individual houses in Vilnius. A biomass boiler house, as an additional heat source, should allow covering the remaining heat demand. energyPRO software is used for system modelling. The paper evaluates heat demand, climate conditions and technical characteristics.Article in Lithuanian

  8. Influence of heat treatment and veneering on the storage modulus and surface of zirconia ceramic

    NARCIS (Netherlands)

    Siavikis, G.; Behr, M.; van der Zel, J.M.; Feilzer, A.J.; Rosentritt, M.

    2011-01-01

    Objectives: Glass-ceramic veneered zirconia is used for the application as fixed partial dentures. The aim of this investigation was to evaluate whether the heat treatment during veneering, the application of glass-ceramic for veneering or long term storage has an influence on the storage modulus of

  9. Quantifying demand flexibility of power-to-heat and thermal energy storage in the control of building heating systems

    DEFF Research Database (Denmark)

    Finck, Christian; Li, Rongling; Kramer, Rick

    2018-01-01

    In the future due to continued integration of renewable energy sources, demand-side flexibility would be required for managing power grids. Building energy systems will serve as one possible source of energy flexibility. The degree of flexibility provided by building energy systems is highly...... restricted by power-to-heat conversion such as heat pumps and thermal energy storage possibilities of a building. To quantify building demand flexibility, it is essential to capture the dynamic response of the building energy system with thermal energy storage. To identify the maximum flexibility a building......’s energy system can provide, optimal control is required. In this paper, optimal control serves to determine in detail demand flexibility of an office building equipped with heat pump, electric heater, and thermal energy storage tanks. The demand flexibility is quantified using different performance...

  10. Verification of heat removal capability of a concrete cask system for spent fuel storage

    Energy Technology Data Exchange (ETDEWEB)

    Mikio, Sakai; Hiroaki, Fujiwara; Tadatsugu, Sakaya; Akira, Sakai [Nuclear Fuel Cycle Development Dept., Nuclear Power Div., Ishikawajima-Harima Heavy Industries Co., Ltd., IHI, Yokohama (Japan)

    2001-07-01

    IHI (Ishikawajima-Harima heavy industries) has developed the concrete cask system that is used for an interim storage facility for spent fuel assemblies generated from nuclear power plants. IHI has designed and fabricated the prototype of a canister and a concrete storage cask, the storage cask consists of reinforced concrete and steel liner. The canister consists of shell, guide tubes and spacer plates mainly. The canister is designed to maintain the integrity of fuel cladding during storage period. Helium gas filled in the canister increases the efficiency of heat removal. A heat shield is equipped in the annulus gap between the canister sidewall and the liner to reduce the radiation heat transferred from the canister surface to the storage cask. The spent fuel decay heat is removed by natural cooling system. Most of the decay heat shall be removed by natural convection air that enters through the four inlet vents at the bottom, then flows through airflow paths and finally outwards to ambient through the four outlet vents at the top. Heat removal experiment on the prototype concrete cask mainly focused on temperature distributions and air flow rates in the storage cask. It is shown that the analytical results are in good agreement with experimental results and that they exceed the experimental results by a few degrees. (A.C.)

  11. Advances in Large-Scale Solar Heating and Long Term Storage in Denmark

    DEFF Research Database (Denmark)

    Heller, Alfred

    2000-01-01

    According to (the) information from the European Large-Scale Solar Heating Network, (See http://www.hvac.chalmers.se/cshp/), the area of installed solar collectors for large-scale application is in Europe, approximately 8 mill m2, corresponding to about 4000 MW thermal power. The 11 plants...... Central Solar Heating Plants, servicing District Heating and related developments in large-scale thermal storage. Central solar heating today is a mature and economic realistic solution for district heating based on a renewable source. The cost for solar collectors has decreased by nearly ¼ during...... the last 10 years and the corresponding cost per collector area for the final installed plant is kept constant, even so the solar production is increased. Unfortunately large-scale seasonal storage was not able to keep up with the advances in solar technology, at least for pit water and gravel storage...

  12. Heat of fusion storage systems for combined solar systems in low energy buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2004-01-01

    of a stable super cooling, i.e. the material is able to cool down below its freezing point (Tfusion) and still be liquid, the possibility exist for a storage with a very low heat loss. When energy is needed from the storage the solidification is activated and the temperature rises almost instantly...... to the melting point. The work within the IEA Task 32 project focuses on the phase change material Sodium Acetate with xanthan rubber. This material melts at 58 °C, which means that low temperature heating systems could make full use of such a storage system. Energy to a large extent can be withdrawn even when...

  13. Achievement of Sustained Net Plasma Heating in a Fusion Experiment with the Optometrist Algorithm.

    Science.gov (United States)

    Baltz, E A; Trask, E; Binderbauer, M; Dikovsky, M; Gota, H; Mendoza, R; Platt, J C; Riley, P F

    2017-07-25

    Many fields of basic and applied science require efficiently exploring complex systems with high dimensionality. An example of such a challenge is optimising the performance of plasma fusion experiments. The highly-nonlinear and temporally-varying interaction between the plasma, its environment and external controls presents a considerable complexity in these experiments. A further difficulty arises from the fact that there is no single objective metric that fully captures both plasma quality and equipment constraints. To efficiently optimise the system, we develop the Optometrist Algorithm, a stochastic perturbation method combined with human choice. Analogous to getting an eyeglass prescription, the Optometrist Algorithm confronts a human operator with two alternative experimental settings and associated outcomes. A human operator then chooses which experiment produces subjectively better results. This innovative technique led to the discovery of an unexpected record confinement regime with positive net heating power in a field-reversed configuration plasma, characterised by a >50% reduction in the energy loss rate and concomitant increase in ion temperature and total plasma energy.

  14. Experimental process investigation of a latent heat energy storage system with a staggered heat exchanger with different phase change materials for solar thermal energy storage applications

    Science.gov (United States)

    Tsolakoglou, Nikolas P.; Koukou, Maria K.; Vrachopoulos, Michalis Gr.; Tachos, Nikolaos; Lymberis, Kostas; Stathopoulos, Vassilis

    2017-11-01

    This work investigates melting and solidification processes of four different Phase Change Materials (PCM) used as latent heat thermal storage system. The experimental rig was consisted of an insulated tank, filled with the under investigation PCM, a staggered heat exchanger to supply or extract heat from the PCM cavity and a water pump to circulate Heat Transfer Fluid (HTF). Both charging (melting) and discharging (solidification) processes were conducted for two different HTF flow rates. The main scope of this work was to develop a first approach and to investigate the behaviour of PCM under various load conditions (different HTF flow rates). Results show that different HTF flow rates affect melting and solidification time periods; in both processes time was reduced while HTF flow rate was increased but in differentways due to the transition from conduction to convection heat transfer mechanisms.

  15. Thermal energy storage - A review of concepts and systems for heating and cooling applications in buildings

    DEFF Research Database (Denmark)

    Pavlov, Georgi Krasimiroy; Olesen, Bjarne W.

    2012-01-01

    period required, economic viability, and operating conditions. One of the main issues impeding the utilization of the full potential of natural and renewable energy sources, e.g., solar and geothermal, for space heating and space cooling applications is the development of economically competitive......The use of thermal energy storage (TES) in buildings in combination with space heating and/or space cooling has recently received much attention. A variety of TES techniques have developed over the past decades. TES systems can provide short-term storage for peak-load shaving as well as long......-term (seasonal) storage for the introduction of natural and renewable energy sources. TES systems for heating or cooling are utilized in applications where there is a time mismatch between the demand and the most economically favorable supply of energy. The selection of a TES system mainly depends on the storage...

  16. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Peng Hu

    2017-02-01

    Full Text Available Electrothermal energy storage (ETES provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analysis results show that the extremum principle of entransy dissipation is an effective criterion for the optimization, and the optimum heat transfer for different cases with the same mass flux or pressure has been discussed. The optimum heat transfer can be achieved by adjusting the mass flux and pressure of the working fluid. It also reveals that with the increase of mass flux, there is a minimum exergy in the range under consideration, and the exergy decreases with the increase of the pressure.

  17. Performance of labyrinth-stratified water-storage system for heating and cooling

    Science.gov (United States)

    Wildin, M. W.

    The feasibility of storing heating or cooling capacity in thermally stratified water contained in rectangular concrete tanks was demonstrated. For the approximately cubical tanks, which were 4.6 meters deep, and for the flow rates which were employed in a diurnal charge-discharge cycle, thermoclines about three feet thick were routinely established during charging and discharging phases of an operating cycle. Linear diffusers were designed to introduce water into the tanks and remove it at low velocity and with a relatively uniform distribution. Thermal efficiency was evaluated. The efficiency realized from cooled storage was in the range from 80 to 90%, while that for heated storage was in the range from 65 to 81%. The higher efficiency of cooled storage is due to several factors, including lower temperature difference to produce energy flow across the boundaries, less internal mixing in storage when the partitions were present and shorter average residence times of energy in storage.

  18. Development of a thermal storage system based on the heat of adsorption of water in hygroscopic materials

    NARCIS (Netherlands)

    Wijsman, A.J.T.M.; Oosterhaven, R.; Ouden, C. den

    1979-01-01

    A thermal storage system based on the heat of adsorption of water in hygroscopic materials has been studied as a component of a solar space heating system. The aim of this project is to decrease the storage volume in comparison with a rock-bed storage system by increasing the stored energy density.

  19. The Analytical Objective Hysteresis Model (AnOHM v1.0: methodology to determine bulk storage heat flux coefficients

    Directory of Open Access Journals (Sweden)

    T. Sun

    2017-07-01

    Full Text Available The net storage heat flux (ΔQS is important in the urban surface energy balance (SEB but its determination remains a significant challenge. The hysteresis pattern of the diurnal relation between the ΔQS and net all-wave radiation (Q∗ has been captured in the Objective Hysteresis Model (OHM parameterization of ΔQS. Although successfully used in urban areas, the limited availability of coefficients for OHM hampers its application. To facilitate use, and enhance physical interpretations of the OHM coefficients, an analytical solution of the one-dimensional advection–diffusion equation of coupled heat and liquid water transport in conjunction with the SEB is conducted, allowing development of AnOHM (Analytical Objective Hysteresis Model. A sensitivity test of AnOHM to surface properties and hydrometeorological forcing is presented using a stochastic approach (subset simulation. The sensitivity test suggests that the albedo, Bowen ratio and bulk transfer coefficient, solar radiation and wind speed are most critical. AnOHM, driven by local meteorological conditions at five sites with different land use, is shown to simulate the ΔQS flux well (RMSE values of ∼ 30 W m−2. The intra-annual dynamics of OHM coefficients are explored. AnOHM offers significant potential to enhance modelling of the surface energy balance over a wider range of conditions and land covers.

  20. Cooling and heating of ultracold neutrons at storage

    CERN Document Server

    Bondarenko, L M; Morozov, V I; Panin, Y N; Geltenbort, P

    2002-01-01

    Rare processes of weak heating and cooling of ultracold neutrons at reflection from a surface of fluoro-substitution oil were investigated. The probability of these processes was estimated as 10 sup - sup 6 for one reflection with a value of transmitted energy comparable with the primary neutron energy. It was shown that weak heating and cooling are realization of a common phenomenon of a quasi-elastic neutron reflection with probability depending on temperature

  1. Maximizing Storage Flexibility in an Aggregated Heat Pump Portfolio

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Nielsen, Kirsten M.; Andersen, Palle

    2014-01-01

    for storage capability. It is of great importance to move energy consumption in time to balance the grid. In this paper a portfolio of houses are modelled and controlled using an aggregated model and a model free scheduling algorithm. Flexibility and ability to trade on the intra-day regulating market...

  2. Improving Geothermal Heat Pump Air Conditioning Efficiency with Wintertime Cooling using Seasonal Thermal Energy Storage (STES). Application Manual

    Science.gov (United States)

    2016-11-01

    APPLICATION MANUAL Improving Geothermal Heat Pump Air Conditioning Efficiency with Wintertime Cooling using Seasonal Thermal Energy Storage...application projects to increase energy efficiency and occupant comfort. Seasonal Thermal Energy Storage (STES) technology, energy efficiency, geothermal heat...electrical energy use (kW-hr) for the geothermal heat pump system with and without a dry fluid cooler

  3. Transient modelling of heat loading of phase change material for energy storage

    Directory of Open Access Journals (Sweden)

    Asyraf W.M.

    2017-01-01

    Full Text Available As the development of solar energy is getting advance from time to time, the concentration solar technology also get the similar attention from the researchers all around the globe. This technology concentrate a large amount of energy into main spot. To collect all the available energy harvest from the solar panel, a thermal energy storage is required to convert the heat energy to one of the purpose such as electrical energy. With the idea of energy storage application that can be narrow down to commercial application such as cooking stove. Using latent heat type energy storage seem to be appropriate with the usage of phase change material (PCM that can release and absorb heat energy at nearly constant temperature by changing its state. Sodium nitrate (NaNO3 and potassium nitrate (KNO3 was selected to use as PCM in this project. This paper focus on the heat loading process and the melting process of the PCM in the energy storage using a computer simulation. The model of the energy storage was created as solid three dimensional modelling using computer aided software and the geometry size of it depend on how much it can apply to boil 1 kg of water in cooking application. The materials used in the tank, heat exchanger and the heat transfer fluid are stainless steel, copper and XCELTHERM MK1, respectively. The analysis was performed using a commercial simulation software in a transient state. The simulation run on different value of velocity but kept controlled under laminar state only, then the relationship of velocity and heat distribution was studied and the melting process of the PCM also has been analyzed. On the effect of heat transfer fluid velocity, the higher the velocity resulted in higher the rate of heat transfer. The comparison between the melting percentages of the PCMs under test conditions show that NaNO3 melts quite faster than KNO3.

  4. Better latent heat and specific heat of stearic acid with magnetite/graphene nanocomposite addition for thermal storage application

    Science.gov (United States)

    Andiarto, R.; Nuryadin, M. K.; Taufik, A.; Saleh, R.

    2017-04-01

    In our previous study, the addition of Magnetite (Fe3O4) into Stearic acid (Sa) as an organic phase change material (PCM) shows an enhancement in the latent heat for thermal energy storage applications. The latent heat of the PCM can also be increased by adding graphene material. Therefore, in this research, the thermal properties of Sa have been studied by the sonication method for several different concentrations of Fe3O4/Graphene nanocomposite additions. The structural properties of all of the samples were observed by X-Ray diffraction (XRD). Melting-solidifying behavior and specific heat value were measured by differential scanning calorimetry (DSC). The thermal degradation process of all samples was investigated by thermogravimetric analysis (TGA). Based on the DSC results, the presence of Fe3O4/Graphene in the Sa enhances the latent heat up to 20%. The specific heat value of the mixture was also found to be increased as the concentration of Fe3O4/Graphene to Sa increased. The TGA results show a lowered thermal degradation process of the Sa by the addition of the Fe3O4/Graphene which indicates a higher thermal stability of the mixture. In conclusion, the results demonstrate that the addition of Fe3O4/Graphene to Sa improves both the sensible heat and the latent heat of the mixture which are very important for thermal energy storage applications

  5. A Novel Modeling of Molten-Salt Heat Storage Systems in Thermal Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Rogelio Peón Menéndez

    2014-10-01

    Full Text Available Many thermal solar power plants use thermal oil as heat transfer fluid, and molten salts as thermal energy storage. Oil absorbs energy from sun light, and transfers it to a water-steam cycle across heat exchangers, to be converted into electric energy by means of a turbogenerator, or to be stored in a thermal energy storage system so that it can be later transferred to the water-steam cycle. The complexity of these thermal solar plants is rather high, as they combine traditional engineering used in power stations (water-steam cycle or petrochemical (oil piping, with the new solar (parabolic trough collector and heat storage (molten salts technologies. With the engineering of these plants being relatively new, regulation of the thermal energy storage system is currently achieved in manual or semiautomatic ways, controlling its variables with proportional-integral-derivative (PID regulators. This makes the overall performance of these plants non optimal. This work focuses on energy storage systems based on molten salt, and defines a complete model of the process. By defining such a model, the ground for future research into optimal control methods will be established. The accuracy of the model will be determined by comparing the results it provides and those measured in the molten-salt heat storage system of an actual power plant.

  6. High-temperature acquifer thermal storage and underground heat storage; IEA ECES Annex 12: Hochtemperatur-Erdwaermesonden- und Aquiferwaermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Sanner, B.; Knoblich, K. [Giessen Univ. (Germany). Inst. fuer Angewandte Geowissenschaften; Koch, M.; Adinolfi, M. [Stuttgart Univ. (Germany). Inst. fuer Siedlungswasserbau, Wasserguete und Abfallwirtschaft

    1998-12-31

    Heat storage is essential for the reconciliation of heat supply and demand. The earth has already proved to be an excellent medium for storing large amounts of heat over longer periods of time, for instance during the cold and hot season. The efficiency of the storage is the better the lower storage losses are at high temperature levels. Unfortunately this can not be easily achieved. While thermal underground stores, which are widely used for cold storage, have proved to perform quite well at temperatures between 10 C - 40 C, it has been rather difficult to achieve similar results at higher temperatures up to 150 C as test and demonstration plants of the 1980s proved. This issue has again attracted so much interest that the IEA launched a project on high temperature underground storage in December 1998. (orig.) [Deutsch] Waermespeicherung ist von entscheidender Bedeutung, wenn es darum geht, ein Waermeangebot mit einer Waermenachfrage zeitlich zur Deckung zu bringen. Der Untergrund hat sich schon seit vielen Jahren als ein geeignetes Medium erwiesen, groessere Waermepumpen ueber laengere Zeitraeume wie etwa die kalten und warmen Jahreszeiten zu speichern. Die Effizienz eines solchen Speichers steigt mit der Hoehe des erreichten Temperaturniveaus und mit sinkenden Speicherverlusten, was leider eher gegenlaeufige Erscheinungen sind. Waehrend thermische Untergrundspeicher im Temperaturbereich von 10-40 C inzwischen erfolgreich demonstriert wurden und vor allem zur Kaeltespeicherung auch bereits vielfach eingesetzt werden, haben hoehere Temperaturen bis etwa 150 C in den Versuchs- und Demonstrationsanlagen der 80er Jahre vielfaeltige Probleme bereitet. Im Gefolge eines erneuten Interesses an unterirdischer thermischer Energiespeicherung wurde im Dezember 1997 ein Vorhaben des IEA Energiespeicherprogramms zu Untergrund-Waermespeichern hoeherer Temperatur eingerichtet. (orig.)

  7. Full Scale Investigation of the Dynamic Heat Storage of Concrete Decks with PCM and Enhanced Heat Transfer Surface Area

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2013-01-01

    The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...... can result in the increased heat amount that can be transferred and stored in the heavy construction element during the diurnal indoor temperature fluctuations.......The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...

  8. Basic Research on a Latent Heat Thermal Energy Storage by Direct Contact Melting and Solidification

    Science.gov (United States)

    Saito, Akihiro; Saito, Akio; Utaka, Yoshio; Okuda, Kenichi; Katayama, Kozo

    A basic experimental research on a latent heat thermal energy storage system, utilizing a simple and effective heat exchange mechanism by a direct contact between the phase change material (PCM) and the heat transfer fluid (HTF) , was shown. In this report, authors proposed the direct contact latent heat thermal energy storage system using industrial paraffin and n-Eicosane as the PCM, and using water as the HTF. The observations were performed concerning the HTF separation from the solid PCM in the solidification process (heat discharging process), and concerning the water pass formation within the solid PCM. Then, it was confirmed that the system worked effectively by using n-Eicosane as the PCM. And authors discussed the mechanism of direct contact solidification process from experimental results.

  9. Surface Oxide Net Charge of a Titanium Alloy; Comparison Between Effects of Treatment With Heat or Radiofrequency Plasma Glow Discharge

    Science.gov (United States)

    MacDonald, Daniel E.; Rapuano, Bruce E.; Schniepp, Hannes C.

    2010-01-01

    In the current study, we have compared the effects of heat and radiofrequency plasma glow discharge (RFGD) treatment of a Ti6Al4V alloy on the physico-chemical properties of the alloy’s surface oxide. Titanium alloy (Ti6Al4V) disks were passivated alone, heated to 600 °C, or RFGD plasma treated in pure oxygen. RFGD treatment did not alter the roughness, topography, elemental composition or thickness of the alloy’s surface oxide layer. In contrast, heat treatment altered oxide topography by creating a pattern of oxide elevations approximately 50–100 nm in diameter. These nanostructures exhibited a three-fold increase in roughness compared to untreated surfaces when RMS roughness was calculated after applying a spatial high-pass filter with a 200 nm cutoff wavelength. Heat treatment also produced a surface enrichment in aluminum and vanadium oxides. Both RFGD and heat treatment produced similar increases in oxide wettability. Atomic force microscopy (AFM) measurements of metal surface oxide net charge signified by a long range force of attraction to or repulsion from a (negatively charged) silicon nitride AFM probe were also obtained for all three experimental groups. Force measurements showed that the RFGD-treated Ti6Al4V samples demonstrated a higher net positive surface charge at pH values below 6 and a higher net negative surface charge at physiological pH (pH values between 7 and 8) compared to control and heat-treated samples These findings suggest that RFGD treatment of metallic implant materials can be used to study the role of negatively charged surface oxide functional groups in protein bioactivity, osteogenic cell behavior and osseointegration independently of oxide topography. PMID:20880672

  10. Using Heat Pump Energy Storages in the Power Grid

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Andersen, Palle; Nielsen, Kirsten M.

    2011-01-01

    The extensive growth of installed wind energy plants lead to increasing balancing problems in the power grid due to the nature of wind fields and diurnal variations in consumption. One way to overcome these problems is to move consumption to times where wind power otherwise cause overproduction...... and large fluctuations in prices. The paper presents a method which takes advantage of heat capacity in single-family houses using heat pumps which are anticipated to be installed in large numbers in Denmark in next decade. This type of heating gives a large time constant and it is shown possible to move...... consumption without compromising the comfort of house residents. In the paper an optimization exploiting forecasts of weather and energy prices combined with prediction models of house dynamics is presented. The results show that with the presented method it will be possible to move a substantial amount...

  11. Organic Rankine Cycle with Solar Heat Storage in Paraffin Way

    Directory of Open Access Journals (Sweden)

    Constantin LUCA

    2015-06-01

    Full Text Available The paper presents an electricity generation system based on an Organic Rankine Cycle and proposed storing the amount of the heat produced by the solar panels using large volume of paraffin wax. The proposed working fluid is R-134a refrigerant. The cycle operates at very low temperatures. A efficiency of 6,55% was obtained.

  12. Adsorption properties of porous materials for solar thermal energy storage and heat pump applications

    OpenAIRE

    Jänchen, Jochen; Stach, Helmut

    2012-01-01

    The water adsorption properties of modified porous sorbents for solar thermal energy storage and heat transformation have been investigated by thermogravimetry (TG) differential thermogravimetry (DTG), microcalorimetry, measurements of water adsorption isotherms, and storage tests. A chabazite type SAPO, a dealuminated faujasite type zeolite, and a mesostructured aluminosilicate, have been synthesized and compared with common zeolites X, Y and silica gel. It has been found that optimized latt...

  13. Temperature dependency of the thermal conductivity of porous heat storage media

    Science.gov (United States)

    Hailemariam, Henok; Wuttke, Frank

    2017-10-01

    Analyzing the variation of thermal conductivity with temperature is vital in the design and assessment of the efficiency of sensible heat storage systems. In this study, the temperature variation of the thermal conductivity of a commercial cement-based porous heat storage material named - Füllbinder L is analyzed in saturated condition in the temperature range between 20 to 70°C (water based storage) with a steady state thermal conductivity and diffusivity meter. A considerable decrease in the thermal conductivity of the saturated sensible heat storage material upon increase in temperature is obtained, resulting in a significant loss of system efficiency and slower loading/un-loading rates, which when unaccounted for can lead to the under-designing of such systems. Furthermore, a new empirical prediction model for the estimation of thermal conductivity of cement-based porous sensible heat storage materials and naturally occurring crystalline rock formations as a function of temperature is proposed. The results of the model prediction are compared with the experimental results with satisfactory results.

  14. Heat transfer enhancement through PCM thermal storage by use of copper fins

    Directory of Open Access Journals (Sweden)

    Rudonja Nedžad R.

    2016-01-01

    Full Text Available Enhancement of heat transfer over a cylinder shaped thermal energy storage filled by paraffin E53 by use of radial rectangular copper fins was analyzed. The thermo-physical features of the storage material are determined in separate experiments and implemented to Fluent software over UDF. Advanced thermal storage geometry comprehension and optimization required introduction of a parameter suitable for the analysis of heat transfer enhancement, so the ratio of heat transfer surfaces as a factor was proposed and applied. It is revealed that increase of the ratio of heat transfer surfaces leads to the decrease of melting time and vice versa. Numerical analysis, employing the 3D model built in Ansys software, observed storage reservoir geometries with variable number of longitudinal radial fins. The adjusted set of boundary conditions was carried out and both written in C language and implemented over UDF in order to define variable heat flux along the height of the heater. The comparison of acquired numerical and experimental results showed a strong correlation. Experimental validation of numerical results was done on the real TES apparatus. [Projekat Ministarstva nauke Republike Srbije, br. III42011, TR 33042 i OI 176006

  15. Adaptive heat pump and battery storage demand side energy management

    Science.gov (United States)

    Sobieczky, Florian; Lettner, Christian; Natschläger, Thomas; Traxler, Patrick

    2017-11-01

    An adaptive linear model predictive control strategy is introduced for the problem of demand side energy management, involving a photovoltaic device, a battery, and a heat pump. Moreover, the heating influence of solar radiation via the glass house effect is considered. Global sunlight radiation intensity and the outside temperature are updated by weather forecast data. The identification is carried out after adapting to a time frame witch sufficiently homogeneous weather. In this way, in spite of the linearity an increase in precision and cost reduction of up to 46% is achieved. It is validated for an open and closed loop version of the MPC problem using real data of the ambient temperature and the global radiation.

  16. Adaptive heat pump and battery storage demand side energy management

    Directory of Open Access Journals (Sweden)

    Sobieczky Florian

    2017-01-01

    Full Text Available An adaptive linear model predictive control strategy is introduced for the problem of demand side energy management, involving a photovoltaic device, a battery, and a heat pump. Moreover, the heating influence of solar radiation via the glass house effect is considered. Global sunlight radiation intensity and the outside temperature are updated by weather forecast data. The identification is carried out after adapting to a time frame witch sufficiently homogeneous weather. In this way, in spite of the linearity an increase in precision and cost reduction of up to 46% is achieved. It is validated for an open and closed loop version of the MPC problem using real data of the ambient temperature and the global radiation.

  17. Annual and Seasonal Variability of Net Heat Budget in the Northern Indian Ocean

    Science.gov (United States)

    Pinker, Rachel T.; Bentamy, Abderrahim; Chen, Wen; Kumar, M. R. Ramesh; Mathew, Simi; Venkatesan, Ramasamy

    2017-04-01

    In this study we investigate the spatial and temporal features of the net heat budget over the Northern Indian Ocean (focusing on the Arabian Sea and the Bay of Bengal), using satellite and numerical model estimates. The main objective is to characterize the annual, seasonal, and inter-annual patterns over this basin of climatic significance. To assess the temporal variability, several turbulent and radiative fluxes are used The turbulent fluxes are based on information from the Institut Français pout la Recherche et l'Exploitation de la MER (IFREMER V3), the Hamburg Ocean-Atmosphere Parameters from Satellite (HOAPS V3), the SEAFLUX V1, the Japanese Ocean Flux Data sets with Use of Remote Sensing Observations (J-OFURO V2), the Objective Analysis Fluxes (OAFlux V2), the European Center for Medium Weather Forecasts (ECMWF), the ERA Interim, the National centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis, CFSR, and the National Aeronautics Space Administration (NASA) Modern Era Retrospective Analysis for Research and Application (MERRA). The radiative fluxes, both shortwave and longwave, include those produced at the University of Maryland (UMD) as well as those derived from several of the above mentioned numerical models. An attempt will be made to evaluate the various fluxes against buoy observations such as those from the RAMA array. The National Institute of Ocean Technology, Chennai, India under its Ocean Observation Program has deployed a series of OMNI Buoys both in the Arabian Sea and the Bay of Bengal. These buoys are equipped with sensors to measure the radiation as well as other parameters. Comparison has been done with the OMNI observations and good agreement has been found with the current set-up of the instrument at a 3 m level. We found significant differences between the various products at specific locations. The ultimate objective is to investigates the sources of the differences in terms of atmospheric variables (surface

  18. Thermal storage in a heat pump heated living room floor for urban district power balancing - effects on thermal comfort, energy loss and costs for residents

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; de Wit, J.B.; Fink, J.; Smit, Gerardus Johannes Maria

    2014-01-01

    For the Dutch smart grid demonstration project Meppelenergie, the effects of controlled thermal energy storage within the floor heating structure of a living room by a heat pump are investigated. Storage possibilities are constrained by room operative and floor temperatures. Simulations indicate

  19. Dynamic modeling of а heating system using geothermal energy and storage tank

    Directory of Open Access Journals (Sweden)

    Milanović Predrag D.

    2012-01-01

    Full Text Available This paper analyzes a greenhouse heating system using geothermal energy and storage tank and the possibility of utilization of insufficient amount of heat from geothermal sources during the periods with low outside air temperatures. Crucial for these analyses is modelling of the necessary yearly energy requirements for greenhouse heating. The results of these analyses enable calculation of an appropriate storage tank capacity so that the energy efficiency of greenhouse heating system with geothermal energy could be significantly improved. [Acknowledgement. This work was supported by Ministry of Science and Technology Development of the Republic of Serbia through the National Energy Efficiency Program (Grant 18234 A. The authors are thankful to the stuff and management of the Company “Farmakom MB PIK 7. juli - Debrc” for their assistance during the realization of this project.

  20. Field evaluation and assessment of thermal energy storage for residential space heating

    Science.gov (United States)

    Hersh, H. N.

    1982-02-01

    A data base was developed based on two heating seasons and 45 test and 30 control homes in Maine and Vermont. Based on first analysis of monitored temperatures and electrical energy used for space heating, fuel bills and reports of users and utilities, the technical performance of TES ceramic and hydronic systems is deemed to be technically satisfactory and there is a high degree of customer acceptance and positive attitudes towards TES. Analysis of house data shows a high degree of variability in electric heat energy demand for a given degree-day. An analysis is underway to investigate relative differences in the efficiency of electricity utilization of storage and direct heating devices. The much higher price of storge systems relative to direct systems is an impediment to market penetration. A changing picture of rate structures may encourage direct systems at the expense of storage systems.

  1. Solar heating and cooling system with absorption chiller and low temperature latent heat storage: Energetic performance and operational experience

    Energy Technology Data Exchange (ETDEWEB)

    Helm, M.; Keil, C.; Hiebler, S.; Mehling, H.; Schweigler, C. [Bavarian Center for Applied Energy Research (ZAE Bayern) (Germany)

    2009-06-15

    Absorption cooling systems based on water/lithium bromide (LiBr) solution typically require an open wet cooling tower to transfer the reject heat to the ambient. Yet, water consumption, the need for water make-up and cleaning, formation of fog, and the risk of Legionella bacteria growth are hindering factors for the implementation of small solar cooling systems. The application of a latent heat storage supporting the heat rejection of the absorption chiller in conjunction with a dry cooling system allows eliminating the wet cooling tower. By that means heat rejection of the chiller is shifted to periods with lower ambient temperatures, i.e. night time or off-peak hours. The system concept and the hydraulic scheme together with an analysis of the energetic performance of the system are presented, followed by a report on the operation of a first pilot installation. (author)

  2. Numerical analysis of a coupled solar collector latent heat storage unit using various phase change materials for heating the water

    Energy Technology Data Exchange (ETDEWEB)

    El Qarnia, Hamid [Universite Cadi Ayyad, Faculte des Sciences Semlalia, Departement de Physique, Laboratoire de Mecanique des Fluides et d' energetique, B.P., 2390 Marrakech (Morocco)

    2009-02-15

    A theoretical model based on the energy equations was developed to predict the thermal behaviour and performance of a solar latent heat storage unit (LHSU) consisting of a series of identical tubes embedded in the phase change material (PCM). During charging mode, a heat transfer fluid (hot water) from the solar collector passes through the tubes and transfers the collecting heat of solar radiation to the PCM. The heat stored in the liquid PCM is next transferred to water during discharging mode to produce heating water. A simulation program based on the finite volume approach was also developed to numerically evaluate the thermal performance of the LHSU. The model was first validated by comparing the results of numerical simulations to the experimental data. A series of numerical simulations were conducted for three kinds of PCM (n-octadecane, Paraffin wax and Stearic acid) to find the optimum design for a given summer climatic conditions of Marrakech city: solar radiation and ambient temperature. Optimization of the LHSU involves determination of the mass of the PCM, the number of tubes, and the flow rate water in solar collector that maximise the thermal storage efficiency. Several simulations were also made to study the effect of the flow rate water on its outlet temperature, during the discharging mode. (author)

  3. Thermal energy storage system using phase change materials: Constant heat source

    Directory of Open Access Journals (Sweden)

    Reddy Meenakshi R.

    2012-01-01

    Full Text Available The usage of phase change materials (PCM to store the heat in the form of latent heat is increased, because large quantity of thermal energy is stored in smaller volumes. In the present experimental investigation paraffin and stearic acid are employed as PCMs in thermal energy storage (TES system to store the heat as sensible and latent heat also. A constant heat source is used to supply heat transfer fluid (HTF at constant temperature to the TES system. In the TES system PCMs are stored in the form of spherical capsules of 38 mm diameter made of high density poly ethylene (HDPE. The results of the investigation are related to the charging time and recovery of stored energy from the TES system.

  4. Experimental studies on seasonal heat storage based on stable supercooling of a sodium acetate water mixture

    DEFF Research Database (Denmark)

    Furbo, Simon; Dragsted, Janne; Fan, Jianhua

    2011-01-01

    Laboratory tests of a 230 l seasonal heat storage module with a sodium acetate water mixture have been carried out. The aim of the tests is to elucidate how best to design a seasonal heat storage based on the salt water mixture, which supercools in a stable way. The module can be a part...... of a seasonal heat storage, that will be suitable for solar heating systems which can fully cover the yearly heat demand of Danish low energy buildings. The tested module has approximately the dimensions 2020 mm x 1285 mm x 80 mm. The module material is steel and the wall thickness is 2 mm. Different methods...... to transfer heat to and from the module have been tested. Further, a solidification start method, based on a strong cooling of a small part of the salt water mixture in the module by boiling CO2 in a small brass tank in good thermal contact to the outer side of the module wall, has been tested. Tests...

  5. Eutectic mixtures of capric acid and lauric acid applied in building wallboards for heat energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Lv Shilei; Zhu Neng [Tianjin University (China). School of Environmental Science and Technology; Feng Guohui [Shenyang Jianzhu University, Shenyang (China)

    2006-06-15

    Capric acid (CA) and lauric acid (LA), as phase change materials (PCM), can be applied for energy storage in low temperature. The phase transitions temperature and values of latent heat of eutectic mixtures of CA and LA are suitable for being incorporated with building materials to form phase change wallboards used for building energy storage. 120, 240 and 360 accelerated thermal cycle tests were conducted to study the changes in latent heat of fusion and melting temperature of phase change wallboards combined with the eutectic mixtures of CA and LA. Differential scanning calorimetry (DSC) tested the transition temperature and latent heat. The results showed that the melting temperature and latent heat of these phase change wallboards with eutectic mixtures have not obvious variations after repeated 360 thermal cycles, which proved that these phase change wallboards have good thermal stability for melting temperature and variations in latent heat of fusion for long time application. Therefore, they can be used for latent heat storage in the field of building energy conservation. (author)

  6. Eutectic mixtures of capric acid and lauric acid applied in building wallboards for heat energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Shilei, L.; Neng, Z. [School of Environment Science and Technology, Tianjin University, Tianjin (China); Guohui, F. [Shenyang Jianzhu University, Shenyang (China)

    2006-07-01

    Capric acid (CA) and lauric acid (LA), as phase change materials (PCM), can be applied for energy storage in low temperature. The phase transition temperature and values of latent heat of eutectic mixtures of CA and LA are suitable for being incorporated with building materials to form phase change wallboards used for building energy storage. 120, 240 and 360 accelerated thermal cycle tests were conducted to study the changes in latent heat of fusion and melting temperature of phase change wallboards combined with the eutectic mixtures of CA and LA. Differential scanning calorimetry (DSC) tested the transition temperature and latent heat. The results showed that the melting temperature and latent heat of these phase change wallboards with eutectic mixtures have no obvious variations after repeated 360 thermal cycles, which proved that these phase change wallboards have good thermal stability for melting temperature and variations in latent heat of fusion for long time application. Therefore, they can be used for latent heat storage in the field of building energy conservation. (author)

  7. A new mobilized energy storage system for waste heat recovery: Case study in Aerla, Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Weilong Wang; Jinyue Yan; Dahlquist, Erik (Maelardalen Univ., Vaesteraas (Sweden)). E-mail: weilong.wang@mdh.se; Jenny Nystroem (Eskilstuna Energi och Miljoe AB, Eskilstuna (Sweden))

    2009-07-01

    This paper introduces a new mobilized thermal energy storage (M-TES) for the recovery of industrial waste heat for distributed heat supply to the distributed users which have not been connected to the district heating network. In the M-TES system, phase-change materials (PCM) are used as the energy storage and carrier to transport the waste heat from the industrial site to the end users by a lorry. A technical feasibility and economic viability of M-TES has been conducted with the comparison of the district heating system as a reference. Thermal performance and cost impacts by different PCM materials have been analyzed compared, aiming at determining the optimum operation conditions. A case study is investigated by utilizing the waste heat from a combine heat and power (CHP) plant for the distributed users which are located at over 30 kilometers away from the plant. The results show that the M-TES may offer a competitive solution compared to building or extending the existing district heating network

  8. Smart solar tanks - Heat storage of the future?

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    1997-01-01

    Preliminary investigations of a smart solar tank concept for small SDHW-systems have been carried out. In the tank the operation of the auxiliary energy supply system is controlled by the hot water demand and by the consumption pattern. Water at the top of the tank is only heated by the auxiliary...... be selected by the owner of the system. Preliminary tests of a 175 l smart solar tank have been carried out. Finally, theoretical calculations of the yearly thermal performances of small SDHW-systems based on standard tanks and on a smart solar tank have been carried out. Based on the investigations...... recommendations for future development work are given....

  9. Thermal energy storage for low grade heat in the organic Rankine cycle

    Science.gov (United States)

    Soda, Michael John

    Limits of efficiencies cause immense amounts of thermal energy in the form of waste heat to be vented to the atmosphere. Up to 60% of unrecovered waste heat is classified as low or ultra-low quality, making recovery difficult or inefficient. The organic Rankine cycle can be used to generate mechanical power and electricity from these low temperatures where other thermal cycles are impractical. A variety of organic working fluids are available to optimize the ORC for any target temperature range. San Diego State University has one such experimental ORC using R245fa, and has been experimenting with multiple expanders. One limitation of recovering waste heat is the sporadic or cyclical nature common to its production. This inconsistency makes sizing heat recovery ORC systems difficult for a variety of reasons including off-design-point efficiency loss, increased attrition from varying loads, unreliable outputs, and overall system costs. Thermal energy storage systems can address all of these issues by smoothing the thermal input to a constant and reliable level and providing back-up capacity for times when the thermal input is deactivated. Multiple types of thermal energy storage have been explored including sensible, latent, and thermochemical. Latent heat storage involves storing thermal energy in the reversible phase change of a phase change material, or PCM, and can have several advantages over other modalities including energy storage density, cost, simplicity, reliability, relatively constant temperature output, and temperature customizability. The largest obstacles to using latent heat storage include heat transfer rates, thermal cycling stability, and potentially corrosive PCMs. Targeting 86°C, the operating temperature of SDSU's experimental ORC, multiple potential materials were explored and tested as potential PCMs including Magnesium Chloride Hexahydrate (MgCl2˙6H2O), Magnesium Nitrate Hexahydrate (Mg(NO3)2˙6H 2O), montan wax, and carnauba wax. The

  10. Downward Heat Penetration below Seasonal Thermocline and its Impact on Sea Surface Temperature Variation Affected by Net Heat Flux during Summer Season

    Science.gov (United States)

    Hosoda, S.; Nonaka, M.; Tomita, T.; Taguchi, B.; Tomita, H.; Iwasaka, N.

    2016-02-01

    Oceanic heat capacity of the upper layer is a key of the change in the sea surface temperature (SST) affecting air-sea heat exchange and of the temporal scale of SST variability. In the past, studies of SST variability associated with the air-sea heat exchange have mainly focused on the conditions during the winter, because wintertime deep mixed layer (ML) accumulates a huge amount of heat to the atmosphere. On the contrary, ML during the warming season is thinner than it is during the cooling season, being only a few tens of meters deep at mid- and high- latitudes, bounded by a shallow and sharp seasonal thermocline. Since the ML that directly communicates with the atmosphere is thin, the ocean has been considered to play a passive role in air-sea interactions during the warming season. In this study, we clarified that subsurface ocean plays an important role to seasonal changes of SST and heat capacity during the warming season using observational data of Argo and J-OFURO2, which is net heat flux (Qnet) data from satellites. To clarify the role of upper ocean to the Qnet during summer, we introduce a concept of heat penetration depth (HPD), defined as the depth to which Qnet distinctly penetrates below the seasonal thermocline. Then we assume vertical one dimensional process between Qnet and temporal heat content (HC) change integrating temperature from surface to HPD. The vertical one dimensional process can be assumed in almost mid- and high-latitude NP, and we successfully characterize the heat capacity in terms of the HC above the HPD. The downward heat penetration below the shallow seasonal thermocline is widely found throughout the NP. On the basis of a simple estimation that the amount of heat accumulated by summer Qnet in the NP, about two-thirds of Qnet penetrates below the shallow seasonal thermocline. The effect of heat penetration also makes a magnitude of seasonal change in SST to be smaller, at least a half of that the magnitude under the assumption

  11. Hydration of Magnesium Carbonate in a Thermal Energy Storage Process and Its Heating Application Design

    Directory of Open Access Journals (Sweden)

    Rickard Erlund

    2018-01-01

    Full Text Available First ideas of applications design using magnesium (hydro carbonates mixed with silica gel for day/night and seasonal thermal energy storage are presented. The application implies using solar (or another heat source for heating up the thermal energy storage (dehydration unit during daytime or summertime, of which energy can be discharged (hydration during night-time or winter. The applications can be used in small houses or bigger buildings. Experimental data are presented, determining and analysing kinetics and operating temperatures for the applications. In this paper the focus is on the hydration part of the process, which is the more challenging part, considering conversion and kinetics. Various operating temperatures for both the reactor and the water (storage tank are tested and the favourable temperatures are presented and discussed. Applications both using ground heat for water vapour generation and using water vapour from indoor air are presented. The thermal energy storage system with mixed nesquehonite (NQ and silica gel (SG can use both low (25–50% and high (75% relative humidity (RH air for hydration. The hydration at 40% RH gives a thermal storage capacity of 0.32 MJ/kg while 75% RH gives a capacity of 0.68 MJ/kg.

  12. Experiences in heat pumps combined with thermal storage for buildings in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Hino, T. [Kajima Technical Research Institute, Tokyo (Japan)

    1996-11-01

    The mechanism, application, and benefits of thermal energy storage in Japan were explored. Thermal energy storage has had a long history in Japan, although ice storage buildings are a more recent innovation. There was evidence in the 1980s of industry reluctance to adopt ice storage, it being regarded as a poor performer, however, in more recent years this appears to be changing towards greater acceptance, driven by the proliferation of office automation machinery in buildings, and a corresponding decrease in heating loads. Various ice storage systems were briefly reviewed. The traditional direct-expansion static-ice system was considered superior to more modern systems because it consumes less energy while making ice, and because thermal resistance can be reduced if thinner tubes are used. Evaporating temperatures not lower than -5 degrees C were observed in a system developed as part of a solar-assisted air source. The coefficient of performance was further improved by decreasing the condensing temperature using ambient-energy radiators. The direct contact ice generator, which has the highest heat transfer without costly ice making heat exchangers, also looks very promising, and is generating considerable interest. 4 refs., 7 figs.

  13. Increasing RES Penetration and Security of Energy Supply by Use of Energy Storages and Heat Pumps in Croatian Energy System

    DEFF Research Database (Denmark)

    Krajačić, Goran; Mathiesen, Brian Vad; Duić, Neven

    2010-01-01

    electricity, heat and transport demands, and including renewable energy, power plants, and combined heat and power production (CHP) for district heating. Using the 2007 energy system the wind power share is increased by two energy storage options: Pumped hydro and heat pumps in combination with heat storages......In this paper integration of wind power generation into the Croatian electricity supply is analysed using available technologies. The starting point is a model of the energy system in Croatia in 2007. Comprehensive hour-by-hour energy system analyses are conducted of a complete system meeting....... The results show that such options can enable an increased penetration of wind power. Using pumped hydro storage (PHS) may increase wind power penetration from 0.5 TWh, for existing PHS installations and up to 6 TWh for very large installations. Using large heat pumps and heat storages in combination...

  14. Heat-Storage Modules Containing LiNO3-3H2O and Graphite Foam

    Science.gov (United States)

    Bootle, John

    2008-01-01

    A heat-storage module based on a commercial open-cell graphite foam (Poco-Foam or equivalent) imbued with lithium nitrate trihydrate (LiNO3-3H2O) has been developed as a prototype of other such modules for use as short-term heat sources or heat sinks in the temperature range of approximately 28 to 30 C. In this module, the LiNO3-3H2O serves as a phase-change heat-storage material and the graphite foam as thermally conductive filler for transferring heat to or from the phase-change material. In comparison with typical prior heat-storage modules in which paraffins are the phase-change materials and aluminum fins are the thermally conductive fillers, this module has more than twice the heat-storage capacity per unit volume.

  15. Energy Balance and Heat Storage of Small Shallow Water Bodies in Semi-arid Areas

    NARCIS (Netherlands)

    Abbasi, A.

    2016-01-01

    This research aims at developing a flexible and efficient (numerical) approach for estimating energy balance and heat storage of small shallow lakes in arid and semi-arid regions. To reach to this aim, some numerical methods and improvements in conventional methods were done. Optimizing the methods

  16. GRACE-derived terrestrial water storage depletion associated with the 2003 European heat wave

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Seneviratne, S.I.; Hinderer, J.

    2005-01-01

    water storage depletion observed from GRACE can be related to the record-breaking heat wave that occurred in central Europe in 2003. We validate the measurements from GRACE using two independent hydrological estimates and direct gravity observations from superconducting gravimeters in Europe. All...

  17. The use of solar energy for heating an asphalt storage tank.

    Science.gov (United States)

    1984-01-01

    10,000 gal. asphalt storage tank was equipped with a solar heating system and instrumented to determine its effectiveness over a 12.5-month period. An evaluation of the data indicated that the solar system conserved 25,126 kWh of electrical power dur...

  18. Study on interim storage system to utilize waste heat from spent fuels

    Energy Technology Data Exchange (ETDEWEB)

    Aritomi, Masanori [Tokyo Inst. of Tech. (Japan); Kurokawa, Hideaki; Kamiyama, Yoshinori; Yamanaka, Tsuneyasu

    1997-12-31

    Spent fuels amounting to about 30 tons a year are generated by a 1,000MWe-class light water reactor (LWR). However, the whole amount of spent fuels generated by LWRs cannot be reprocessed. From the viewpoint of energy resources, it is believed in Japan that fast breeder reactors will be introduced as commercial power reactors in the future. In that time, it admits of no doubt that the spent fuel will be a valuable energy resource. It is, therefore, an urgent problem in Japan to establish interim storage systems of spent fuels for LWRs to continue smoothly in operation. In this work, the spent fuel is treated not as unwanted waste but as a heat source. At first, various kinds of interim storage systems of spent fuel are examined from the viewpoint of the utilization of the waste heat, and a pool storage system is dealt with. Next, the possibility of the utilization of the waste heat are examined. Finally, a concept of the interim storage plant, which supplies the heat to a green house where flowers with high value added such as orchids are cultivated, is proposed as a demonstration plant. (author)

  19. A predictive model for smart control of a domestic heat pump and thermal storage

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; Gebhardt, I.; de Wit, J.B.; Smit, Gerardus Johannes Maria

    The purpose of this paper is to develop and validate a predictive model of a thermal storage which is charged by a heat pump and used for domestic hot water supply. The model is used for smart grid control purposes and requires measurement signals of flow and temperature at the inlet and outlet of

  20. Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques.

    Science.gov (United States)

    F.C. Meinzer; J.R. Brooks; J.-C. Domec; B.L. Gartner; J.M. Warren; D.R. Woodruff; K. Bible; D.C. Shaw

    2006-01-01

    The volume and complexity of their vascular systems make the dynamics of tong-distance water transport in large trees difficult to study. We used heat and deuterated water (D20) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii...

  1. Use of infrared thermography for the evaluation of heat losses during coal storage

    NARCIS (Netherlands)

    Fierro, V.; Miranda, J.L.; Romero, C.; Andrés, J.M.; Pierrot, A.; Gómez-Landesa, E.; Arriaga, A.; Schmal, D.

    1999-01-01

    The exothermic processes during coal storage reduce the calorific value of the coal which in turn results in financial losses. An accurate and easy calculation of the losses may be an efficient tool to evaluate the effectiveness of the measures taken to reduce the spontaneous heating of coal and to

  2. heat storage in upper and lower body during high-intensity exercise ...

    African Journals Online (AJOL)

    muscle mass, thermoregulatory neural signals and circulatory function. Understanding SCI thermoregulation physiology would benefit exercise function. Therefore, this study was designed to describe heat storage in the upper and lower bodies of SCI and able-bodied (AB) athletes. Procedure: Seven SCI and 8 AB athletes ...

  3. DYNAMICS OF WATER TRANSPORT AND STORAGE IN CONIFERS STUDIED WITH DEUTERIUM AND HEAT TRACING TECHNIQUES

    Science.gov (United States)

    The volume and complexity of their vascular systems make the dynamics of long-distance water transport difficult to study. We used heat and deuterated water (D2O) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the co...

  4. Sulfur Based Thermochemical Heat Storage for Baseload Concentrated Solar Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Bunsen [General Atomics, San Diego, CA (United States)

    2014-11-01

    This project investigates the engineering and economic feasibility of supplying baseload power using a concentrating solar power (CSP) plant integrated with sulfur based thermochemical heat storage. The technology stores high temperature solar heat in the chemical bonds of elemental sulfur. Energy is recovered as high temperature heat upon sulfur combustion. Extensive developmental and design work associated with sulfur dioxide (SO2) disproportionation and sulfuric acid (H2SO4) decomposition chemical reactions used in this technology had been carried out in the two completed phases of this project. The feasibility and economics of the proposed concept was demonstrated and determined.

  5. Numerical heat transfer studies of the fatty acids for different heat exchanger materials on the performance of a latent heat storage system

    Energy Technology Data Exchange (ETDEWEB)

    Atul Sharma; Lee Dong Won; Jun Un Park [Korea Institute of Energy Research, Daejeon (Korea). Solar Thermal Research Centre; Buddhi, D. [Devi Ahilya University, Indore (India). Thermal Energy Storage Laboratory

    2005-11-01

    Theoretical investigations of fatty acids as a phase change material (PCM) for energy storage system have been conducted in this study. The selected fatty acids were capric acid, lauric acid, myristic acid, palmitic acid and stearic acid. For the two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Glass, stainless steel, tin, aluminium mixed, aluminium and copper were used as heat exchanger materials in the numerical calculations. Theoretical results show that capric acid was found good compatibility with latent heat storage system. The large value of thermal conductivity of heat exchanger materials did not make significant contribution on the melt fraction. (author)

  6. Metal hydride hydrogen and heat storage systems as enabling technology for spacecraft applications

    Energy Technology Data Exchange (ETDEWEB)

    Reissner, Alexander, E-mail: reissner@fotec.at [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan Straße 2, 2700 Wiener Neustadt (Austria); University of Applied Sciences Wiener Neustadt, Johannes Gutenberg-Straße 3, 2700 Wiener Neustadt (Austria); Pawelke, Roland H.; Hummel, Stefan; Cabelka, Dusan [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan Straße 2, 2700 Wiener Neustadt (Austria); Gerger, Joachim [University of Applied Sciences Wiener Neustadt, Johannes Gutenberg-Straße 3, 2700 Wiener Neustadt (Austria); Farnes, Jarle, E-mail: Jarle.farnes@prototech.no [CMR Prototech AS, Fantoftvegen 38, PO Box 6034, 5892 Bergen (Norway); Vik, Arild; Wernhus, Ivar; Svendsen, Tjalve [CMR Prototech AS, Fantoftvegen 38, PO Box 6034, 5892 Bergen (Norway); Schautz, Max, E-mail: max.schautz@esa.int [European Space Agency, ESTEC – Keplerlaan 1, 2201 AZ Noordwijk Zh (Netherlands); Geneste, Xavier, E-mail: xavier.geneste@esa.int [European Space Agency, ESTEC – Keplerlaan 1, 2201 AZ Noordwijk Zh (Netherlands)

    2015-10-05

    Highlights: • A metal hydride tank concept for heat and hydrogen storage is presented. • The tank is part of a closed-loop reversible fuel cell system for space application. • For several engineering issues specific to the spacecraft application, solutions have been developed. • The effect of water contamination has been approximated for Ti-doped NaAlH{sub 4}. • A novel heat exchanger design has been realized by Selective Laser Melting. - Abstract: The next generation of telecommunication satellites will demand a platform payload performance in the range of 30+ kW within the next 10 years. At this high power output, a Regenerative Fuel Cell Systems (RFCS) offers an efficiency advantage in specific energy density over lithium ion batteries. However, a RFCS creates a substantial amount of heat (60–70 kJ per mol H{sub 2}) during fuel cell operation. This requires a thermal hardware that accounts for up to 50% of RFCS mass budget. Thus the initial advantage in specific energy density is reduced. A metal hydride tank for combined storage of heat and hydrogen in a RFCS may overcome this constraint. Being part of a consortium in an ongoing European Space Agency project, FOTEC is building a technology demonstrator for such a combined hydrogen and heat storage system.

  7. Modeling of District Heating Networks for the Purpose of Operational Optimization with Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Leśko Michał

    2017-12-01

    Full Text Available The aim of this document is to present the topic of modeling district heating systems in order to enable optimization of their operation, with special focus on thermal energy storage in the pipelines. Two mathematical models for simulation of transient behavior of district heating networks have been described, and their results have been compared in a case study. The operational optimization in a DH system, especially if this system is supplied from a combined heat and power plant, is a difficult and complicated task. Finding a global financial optimum requires considering long periods of time and including thermal energy storage possibilities into consideration. One of the most interesting options for thermal energy storage is utilization of thermal inertia of the network itself. This approach requires no additional investment, while providing significant possibilities for heat load shifting. It is not feasible to use full topological models of the networks, comprising thousands of substations and network sections, for the purpose of operational optimization with thermal energy storage, because such models require long calculation times. In order to optimize planned thermal energy storage actions, it is necessary to model the transient behavior of the network in a very simple way - allowing for fast and reliable calculations. Two approaches to building such models have been presented. Both have been tested by comparing the results of simulation of the behavior of the same network. The characteristic features, advantages and disadvantages of both kinds of models have been identified. The results can prove useful for district heating system operators in the near future.

  8. Modeling of District Heating Networks for the Purpose of Operational Optimization with Thermal Energy Storage

    Science.gov (United States)

    Leśko, Michał; Bujalski, Wojciech

    2017-12-01

    The aim of this document is to present the topic of modeling district heating systems in order to enable optimization of their operation, with special focus on thermal energy storage in the pipelines. Two mathematical models for simulation of transient behavior of district heating networks have been described, and their results have been compared in a case study. The operational optimization in a DH system, especially if this system is supplied from a combined heat and power plant, is a difficult and complicated task. Finding a global financial optimum requires considering long periods of time and including thermal energy storage possibilities into consideration. One of the most interesting options for thermal energy storage is utilization of thermal inertia of the network itself. This approach requires no additional investment, while providing significant possibilities for heat load shifting. It is not feasible to use full topological models of the networks, comprising thousands of substations and network sections, for the purpose of operational optimization with thermal energy storage, because such models require long calculation times. In order to optimize planned thermal energy storage actions, it is necessary to model the transient behavior of the network in a very simple way - allowing for fast and reliable calculations. Two approaches to building such models have been presented. Both have been tested by comparing the results of simulation of the behavior of the same network. The characteristic features, advantages and disadvantages of both kinds of models have been identified. The results can prove useful for district heating system operators in the near future.

  9. Bed geometries, fueling strategies and optimization of heat exchanger designs in metal hydride storage systems for automotive applications: A review

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Dornheim, Martin; Sloth, Michael

    2014-01-01

    given to metal hydride storage tanks for light duty vehicles, since this application is the most promising one for such storage materials and has been widely studied in the literature. Enhancing cooling/heating during hydrogen uptake and discharge has found to be essential to improve storage systems...

  10. PREPARATION OF PUZZOLANA ACTIVE TWO COMPONENT COMPOSITE FOR LATENT HEAT STORAGE

    Directory of Open Access Journals (Sweden)

    Jan Fort

    2016-10-01

    Full Text Available Application of Phase Change Materials (PCMs represents promising way for an increase of energy efficiency of industrial devices, reduction of energy demands for heating and cooling, waste heat recovery, solar energy storage and smart control of buildings interior climate. In this paper, the potential of diatomite as the bearer for the shape stable PCM was studied in order to develop material applicable in the mix composition of composite materials. Considering availability, endurance and compatibility of diatomite with the cement and lime based materials, preparation of diatomite/wax composite brings pozzolana active PCM with great promises at a reasonable cost. Prepared composite was analysed in detail using laser diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. Also the pozzolanic activity was measured. The prepared two components composite exhibits high latent heat storage and particle size distribution compatible with cement and hydrated lime.

  11. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Shestakov Igor A.

    2015-01-01

    Full Text Available The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characterize the basic regularities of the processes are obtained. Circulating flows are determined and carried out the analysis of vortices formation mechanism and the temperature distribution in solution at conditions of natural convection when the Grashof number (Gr = 106. A significant influence of heat transfer rate on solutions boundary on flow structure and temperature field in LNG storage tanks.

  12. Basic Research on a Latent Heat Thermal Energy Storage by Direct Contact Melting and Soldification

    Science.gov (United States)

    Saito, Akihiro; Saito, Akio; Utaka, Yoshio; Okuda, Kenichi; Katayama, Kozo

    A basic experimental research on a latent heat thermal energy storage system , utilizing a simple and effective heat exchange mechanism by a direct contact between the phase change material (PCM) and the heat transfer fluid (HTF), was shown. Discharging experiments on direct contact latent heat thermal energy reservoir using n-Eicosane as the PCM and water as the HTF, were performed, based on the conditions obtained in previous report. Then, operating conditions for suitable discharging process were searched from the experimental results (outlet water temperature response and local temperature response in the reservoir). Moreover, solidification mechanisms of PCM, which had been presumed in previous report, were confirmed from these experimental results, and the simple physical model on direct contact heat exchange in the reservoir was proposed. Then, the outlet water temperature response by this model was compared with the experimental results.

  13. Parametric Study on the Dynamic Heat Storage Capacity of Building Elements

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Manz, H.; Heiselberg, Per

    2007-01-01

    of onedimensional heat conduction in a slab with convective boundary condition was applied to quantify the dynamic heat storage capacity of a particular building element. The impact of different parameters, such as slab thickness, material properties and the heat transfer coefficient was investigated, as well......In modern, extensively glazed office buildings, due to high solar and internal loads and increased comfort expectations, air conditioning systems are often used even in moderate and cold climates. Particularly in this case, passive cooling by night-time ventilation seems to offer considerable...... potential. However, because heat gains and night ventilation periods do not coincide in time, a sufficient amount of thermal mass is needed in the building to store the heat. Assuming a 24 h-period harmonic oscillation of the indoor air temperature within a range of thermal comfort, the analytical solution...

  14. Thermal energy storage with geothermal triplet for space heating and cooling

    Science.gov (United States)

    Bloemendal, Martin; Hartog, Niels

    2017-04-01

    Many governmental organizations and private companies have set high targets in avoiding CO2 emissions and reducing energy (Kamp, 2015; Ministry-of-Economic-affairs, 2016). ATES systems use groundwater wells to overcome the discrepancy in time between the availability of heat (during summer) and the demand for heat (during winter). Aquifer Thermal Energy Storage is an increasingly popular technique; currently over 2000 ATES systems are operational in the Netherlands (Graaf et al., 2016). High temperature ATES may help to improve performance of these conventional ATES systems. ATES systems use heat pumps to get the stored heat to the required temperature for heating of around 40-50°C and to produce the cold water for cooling in summer. These heat pumps need quite a lot of power to run; on average an ATES system produces 3-4 times less CO2 emission compared to conventional. Over 60% of those emission are accounted for by the heat pump (Dekker, 2016). This heat pump power consumption can be reduced by utilizing other sources of sustainable heat and cooling capacity for storage in the subsurface. At such operating temperatures the required storage temperatures do no longer match the return temperatures in the building systems. Therefore additional components and an additional well are required to increase the groundwater temperature in summer (e.g. solar collectors) and decrease it in winter (e.g. dry coolers). To prevent "pollution" of the warm and cold well return water from the building can be stored in a third well until weather conditions are suitable for producing the required storage temperature. Simulations and an economical evaluation show great potential for this type of aquifer thermal energy storage; economic performance is better than normal ATES while the emissions are reduce by a factor ten. At larger temperature differences, also the volume of groundwater required to pump around is much less, which causes an additional energy saving. Research now

  15. Heat storage enhances efficiency of cogeneration. Chances and problems of heat store use; Waermespeicherung erhoeht die Effizienz der Kraft-Waerme-Kopplung. Chancen und Probleme der Speichernutzung

    Energy Technology Data Exchange (ETDEWEB)

    Dittmann, Achim [Technische Univ. Dresden (Germany). Inst. fuer Energietechnik; Nestke, Claudius [Ingenieurbuero Karla Nestke, Halle (Saale) (Germany)

    2011-01-15

    The optimum integration of electric power from cogeneration systems into the public grid is hardly possible without heat stores. Further, no increase of the market share of renewable energy sources and no integration in existing district heating grids will be possible without heat stores. The authors present their experience in grid storage and in the use of hot water displacement stores.

  16. Investigation of small scale solar concentration parabolic dish with heat storage: (low to medium temperature application

    Energy Technology Data Exchange (ETDEWEB)

    Madessa, Habtamu Bayera

    2012-07-01

    This PhD thesis focuses on the development and testing of a small scale concentrating parabolic dish with heat storage for low to medium temperature applications. The system consists of a parabolic dish solar concentrator that concentrates solar radiation, a fibrous mat solar absorber that captures concentrated solar rays and converts them to thermal energy and a packed bed with pebble rock as a thermal energy storage unit. This research has targeted several issues in which there is a lack of knowledge on small scale concentrating solar energy technologies, with the work summarized in eight papers. Paper 1 concerns experimental measurement of the dynamic temperature profiles along a rock bed heat storage unit during thermal charging and degradation. The study examined both finned and non-finned types of rock bed storages. The effects of the long fins. which are incorporated to transport heat from the bottom to the top surface of the heat storage, were investigated in relation to temperature distribution. As an extension of Paper 1, the performance of a rock bed fitted with long fins was studied as a heat storage unit and a cooking device. The bed charging efficiency, as well as the capacity to store thermal energy and extract heat for boiling of water was discussed. Paper 3 describes the implemention of a 1D numerical model in the MATLAB environment to simulate the transient temperature profiles of rock bed heat storage units. Conservation equations were formulated for the air, rock pebble and fins. The equations were solved on a staggered grid, and the model predicts the experimental results reasonably well. The thesis also investigates two types of volumetric solar absorbers (a fibrous wire mesh and a ceramic) that could be incorporated with a small scale solar concentrating parabolic dish system. Both the fibrous mesh and ceramic type absorbers display a better performance, as discussed in Paper 4. Another contribution of the PhD work is to investigate a 1D sun

  17. Characteristics on the heat storage and recovery by the underground spiral heat exchange pipe; Chichu maisetsu spiral kan ni yoru chikunetsu shunetsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Imai, I. [Kure National College of Technology, Hiroshima (Japan); Taga, M. [Kinki University, Osaka (Japan)

    1996-10-27

    The consistency between the experimental value of a soil temperature and the calculation value of a soil temperature given by a non-steady heat conduction equation was confirmed. The experimental value is obtained by laying a spiral heat exchange pipe in the heat-insulated soil box and circulating hot water forcibly in the pipe. The temperature conductivity in soil significantly influences the heat transfer in soil. The storage performance is improved when the temperature conductivity increases because of the contained moisture. As the difference between the initial soil temperature and circulating water temperature becomes greater, the heat storage and recovery values increase. A thermal core heat transfer is done in the spiral pipe. Therefore, the diameter of the pipe little influences the heat storage performance, and the pitch influences largely. About 50 hours after heat is stored, the storage performance is almost the same as for a straight pipe that uses the spiral diameter as a pipe diameter. To obtain the same heat storage value, the spiral pipe is made of fewer materials than the straight pipe and low in price. The spiral pipe is more advantageous than the straight pipe in the necessary motive power and supply heat of a pump. 1 ref., 11 figs., 1 tab.

  18. Combined Heat and Power Dispatch Considering Heat Storage of Both Buildings and Pipelines in District Heating System for Wind Power Integration

    Directory of Open Access Journals (Sweden)

    Ping Li

    2017-06-01

    Full Text Available The strong coupling between electric power and heat supply highly restricts the electric power generation range of combined heat and power (CHP units during heating seasons. This makes the system operational flexibility very low, which leads to heavy wind power curtailment, especially in the region with a high percentage of CHP units and abundant wind power energy such as northeastern China. The heat storage capacity of pipelines and buildings of the district heating system (DHS, which already exist in the urban infrastructures, can be exploited to realize the power and heat decoupling without any additional investment. We formulate a combined heat and power dispatch model considering both the pipelines’ dynamic thermal performance (PDTP and the buildings’ thermal inertia (BTI, abbreviated as the CPB-CHPD model, emphasizing the coordinating operation between the electric power and district heating systems to break the strong coupling without impacting end users’ heat supply quality. Simulation results demonstrate that the proposed CPB-CHPD model has much better synergic benefits than the model considering only PDTP or BTI on wind power integration and total operation cost savings.

  19. High temperature latent heat thermal energy storage to augment solar thermal propulsion for microsatellites

    Science.gov (United States)

    Gilpin, Matthew R.

    Solar thermal propulsion (STP) offers an unique combination of thrust and efficiency, providing greater total DeltaV capability than chemical propulsion systems without the order of magnitude increase in total mission duration associated with electric propulsion. Despite an over 50 year development history, no STP spacecraft has flown to-date as both perceived and actual complexity have overshadowed the potential performance benefit in relation to conventional technologies. The trend in solar thermal research over the past two decades has been towards simplification and miniaturization to overcome this complexity barrier in an effort finally mount an in-flight test. A review of micro-propulsion technologies recently conducted by the Air Force Research Laboratory (AFRL) has identified solar thermal propulsion as a promising configuration for microsatellite missions requiring a substantial Delta V and recommended further study. A STP system provides performance which cannot be matched by conventional propulsion technologies in the context of the proposed microsatellite ''inspector" requiring rapid delivery of greater than 1500 m/s DeltaV. With this mission profile as the target, the development of an effective STP architecture goes beyond incremental improvements and enables a new class of microsatellite missions. Here, it is proposed that a bi-modal solar thermal propulsion system on a microsatellite platform can provide a greater than 50% increase in Delta V vs. chemical systems while maintaining delivery times measured in days. The realization of a microsatellite scale bi-modal STP system requires the integration of multiple new technologies, and with the exception of high performance thermal energy storage, the long history of STP development has provided "ready" solutions. For the target bi-modal STP microsatellite, sensible heat thermal energy storage is insufficient and the development of high temperature latent heat thermal energy storage is an enabling

  20. Characterisation of the bacterial populations in a saline heat storage aquifer in the North German Basin

    Science.gov (United States)

    Alawi, M.; Lerm, S.; Vetter, A.; Vieth, A.; Mangelsdorf, K.; Seibt, A.; Wolfgramm, M.; Würdemann, H.

    2009-04-01

    The colonization and the ecology of microorganisms in the deep biosphere arouse increasing interest of scientists because of utilizing the subsurface for e.g. energy storage and recovery. The research project AquiScreen investigates the operational reliability of eight geothermally used groundwater systems in Germany under microbial, geochemical, mineralogical, and petrological aspects. This study shows the results of the heat storage in Neubrandenburg (depth: 1250 m), a typical site for saline fluids in the North German Basin. The seasonal alternation in charge and discharge mode enabled sampling the warm (75˚ C) and the cold (45˚ C) side of the geothermal doublet. The analyses focus on microbially induced corrosion on plant components and scaling resulting in filter and/or formation clogging. Microbiological analyses were carried out with fluid and solid phase samples by 16S rDNA based Single Strand Conformation Polymorphism (SSCP) fingerprinting. The analyses are utilized to evaluate the impact of microbial populations on such systems. The genetic fingerprinting revealed significant differences in the bacterial community structure between the warm and cold side of the heat storage. Since the geochemical analyses revealed no remarkable differences, the temperature might be crucial for the different community structures. At the warm side of the aquifer the identified bacteria are closely related to Variovorax and Sphingomonas. At the cold side of the heat storage sulphate reducing and fermentative bacteria were detected. These results correspond with locally observed iron sulphide precipitation and corrosion processes on plant components. Particularly the bacterial population of the cold side was studied over a period of two years. Thereby seasonal changes in the abundance of the identified bacteria, depending on the operational mode of the geothermal plant, were observed. After a malfunction in the pump system of the cold side of the heat storage changes in

  1. Physical properties of ZrC/Al2O3 imbedded heat storage woven fabrics

    Science.gov (United States)

    Kim, S. J.; Song, M. K.; Seo, K. O.; Kim, H. A.

    2017-10-01

    This study investigated different physical properties of ZrC/Al2O3 imbedded heat storage woven fabrics. ZrC and Al2O3 imbedded heat storage PET filaments were spun on the pilot spinning equipment, respectively. Various physical properties of ceramic imbedded fabrics made of ZrC and Al2O3 imbedded filaments were measured and compared with those of the regular PET woven fabric. The surface temperatures of the ZrC and Al2O3 imbedded fabrics were higher than that of the regular fabric. Water absorption rate of ceramic imbedded fabrics was better than that of the regular fabric and drying property was inferior to that of regular fabric. Breathability by water vapour resistance(Ref) of ZrC imbedded fabric was superior to that of regular fabric. Heat keepability rates of the ceramic imbedded fabrics were higher than that of the regular fabrics, which revealed a good heat storage property of the ZrC/Al2O3 imbedded fabrics.

  2. Influence of heat treatment and veneering on the storage modulus and surface of zirconia ceramic.

    Science.gov (United States)

    Siavikis, Georgius; Behr, Michael; van der Zel, Jef M; Feilzer, Albert J; Rosentritt, Martin

    2011-04-01

    Glass-ceramic veneered zirconia is used for the application as fixed partial dentures. The aim of this investigation was to evaluate whether the heat treatment during veneering, the application of glass-ceramic for veneering or long term storage has an influence on the storage modulus of zirconia. Zirconia bars (Cercon, DeguDent, G; 0.5x2x20 mm) were fabricated and treated according to veneering conditions. Besides heating regimes between 680°C and 1000°C (liner bake and annealing), sandblasting (Al(2)O(3)) or steam cleaning were used. The bars were investigated after 90 days storage in water and acid. For investigating the influence of veneering, the bars were veneered in press- or layer technique. Dynamic mechanical analysis (DMA) in a three-point-bending design was performed to determine the storage modulus between 25°C and 200°C at a frequency of 1.66 Hz. All specimens were loaded on top and bottom (treatment on pressure or tensile stress side). Scanning electron microscopy (SEM) was used for evaluating the superficial changes of the zirconia surface due to treatment. Statistical analysis was performed using Mann Whitney U-test (α=0.05). Sintered zirconia provided a storage modulus E' of 215 (203/219) GPa and tan δ of 0.04 at 110°C. A 10%-decrease of E' was found up to 180°C. The superficial appearance changed due to heating regime. Sandblasting reduced E' to 213 GPa, heating influenced E' between 205 GPa (liner bake 1) and 222 GPa (dentin bake 1). Steam cleaning, annealing and storage changed E' between 4 GPa and 22 GPa, depending on the side of loading. After veneering, strong E'-reduction was found down to 84 GPa and 125 GPa. Veneering of zirconia with glass-ceramic in contrast to heat treating during veneering procedure had a strong influence on the modulus. The application of the glass-ceramic caused a stronger decrease of the storage modulus.

  3. Thermo-Hydraulic Analysis of Heat Storage Filled with the Ceramic Bricks Dedicated to the Solar Air Heating System.

    Science.gov (United States)

    Nemś, Magdalena; Nemś, Artur; Kasperski, Jacek; Pomorski, Michał

    2017-08-12

    This article presents the results of a study into a packed bed filled with ceramic bricks. The designed storage installation is supposed to become part of a heating system installed in a single-family house and eventually to be integrated with a concentrated solar collector adapted to climate conditions in Poland. The system's working medium is air. The investigated temperature ranges and air volume flow rates in the ceramic bed were dictated by the planned integration with a solar air heater. Designing a packed bed of sufficient parameters first required a mathematical model to be constructed and heat exchange to be analyzed, since heat accumulation is a complex process influenced by a number of material properties. The cases discussed in the literature are based on differing assumptions and different formulas are used in calculations. This article offers a comparison of various mathematical models and of system operating parameters obtained from these models. The primary focus is on the Nusselt number. Furthermore, in the article, the thermo-hydraulic efficiency of the investigated packed bed is presented. This part is based on a relationship used in solar air collectors with internal storage.

  4. HEAT STORAGE SYSTEM WITH PHASE CHANGE MATERIALS IN COGENERATION UNITS: STUDY OF PRELIMINARY MODEL

    Directory of Open Access Journals (Sweden)

    Claudio Caprara

    2008-12-01

    Full Text Available The continuous increase in the mechanization of farm activities, the rise in fuel prices and the environmental aspects concerning gas emissions are the main driving forces behind efforts toward more effective use of renewable energy sources and cogeneration systems even in agricultural and cattle farms. Nevertheless these systems are still not very suitable for this purpose because of their little flexibility in following the changing energy demand as opposed to the extremely various farm load curves, both in daytime and during the year. In heat recovery systems, the available thermal energy supply is always linked to power production, thus it does not usually coincide in time with the heat demand. Hence some form of thermal energy storage (TES is necessary in order to reach the most effective utilization of the energy source. This study deals with the modelling of a packed bed latent heat TES unit, integrating a cogeneration system made up of a reciprocating engine. The TES unit contains phase change materials (PCMs filled in spherical capsules, which are packed in an insulated cylindrical storage tank. Water is used as heat transfer fluid (HTF to transfer heat from the tank to the final uses, and exhausts from the engine are used as thermal source. PCMs are considered especially for their large heat storage capacity and their isothermal behaviour during the phase change processes. Despite their high energy storage density, most of them have an unacceptably low thermal conductivity, hence PCMs encapsulation technique is adopted in order to improve heat transfer. The special modular configuration of heat exchange tubes and the possibility of changing water flow through them allow to obtain the right amount of thermal energy from the tank, according to the hourly demand of the day. The model permits to choose the electrical load of the engine, the dimensions of the tank and the spheres, thickness and diameter of heat exchanger and the nature of

  5. APPLICATIONS OF THERMAL ENERGY STORAGE TO WASTE HEAT RECOVERY IN THE FOOD PROCESSING INDUSTRY, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, W. L.; Christenson, James A.

    1979-07-31

    A project is discussed in which the possibilities for economical waste heat recovery and utilization in the food industry were examined. Waste heat availability and applications surveys were performed at two manufacturing plants engaged in low temperature (freezing) and high temperature (cooking, sterilizing, etc.) food processing. The surveys indicate usable waste heat is available in significant quantities which could be applied to existing, on-site energy demands resulting in sizable reductions in factory fuel and energy usage. At the high temperature plant, the energy demands involve the heating of fresh water for boiler make-up, for the food processes and for the daily clean-up operation. Clean-up poses an opportunity for thermal energy storage since waste heat is produced during the one or two production shifts of each working day while the major clean-up effort does not occur until food production ends. At the frozen food facility, the clean-up water application again exists and, in addition, refrigeration waste heat could also be applied to warm the soil beneath the ground floor freezer space. Systems to recover and apply waste heat in these situations were developed conceptually and thermal/economic performance predictions were obtained. The results of those studies indicate the economics of waste heat recovery can be attractive for facilities with high energy demand levels. Small factories, however, with relatively low energy demands may find the economics marginal although, percentagewise, the fuel and energy savings are appreciable.

  6. High resolution numerical modelling of high temperature heat storage in geological media

    Science.gov (United States)

    Boockmeyer, Anke; Bauer, Sebastian

    2014-05-01

    Increasing use of energy stemming from renewable sources, such as wind or solar power plants, requires development of new and improvement of existing energy storage options on different time scales. One potential storage option is high temperature heat storage with temperatures of up to 100°C in the geological subsurface using borehole heat exchanger (BHE). Numerical scenario simulations are performed to assess feasibility and storage capacity and, furthermore, to predict the effects induced. To allow for accurate and reliable results, the BHE must be represented correctly and realistic in the numerical model. Therefore, a detailed model of a single BHE and the surrounding aquifer, accounting for the full geometry and component parametrisation (circulating working fluid, pipe and grout), is set up. This model setup is used to simulate an experimental data set from a laboratory sandbox by Beier et al. (2011), containing an 18 m long single U-tube BHE centered horizontally along it. Temperature curves observed in different radial distances as well as at the pipe outflow can be matched well with the model setup used, which is thus verified. Potential geological formations for high temperature heat storage are located in greater depths below fresh water aquifers that are used for drinking water. Therefore, the above model is adapted to represent a 100 m long vertical double U-tube BHE placed in an average depth of 500 m. The processes of heat transport and groundwater flow are coupled by water density and viscosity, which both depend on pressure and temperature. A sensitivity study is done to quantify the effects of the thermal parameters of grout and aquifer on the amount of heat stored and the temperature distribution in the aquifer. It was found that the amount of heat stored through the BHE is most sensitive to the heat conductivity of the aquifer. Increasing the aquifer heat conductivity by 50 % increases the amount of heat stored in the numerical model by 30

  7. Latent heat storage modules for preheating internal combustion engines: application to a bus petrol engine

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L.L.; Burak, V.S.; Kulakov, A.G.; Mishkinis, D.A.; Bohan, P.V. [Luikov Heat and Mass Transfer Institute, Minsk (Belarus)

    2000-07-01

    The heat storage (HS) system for pre-heating a bus petrol engine before its ignition was mathematically modelled and experimentally investigated. The development of such devices is an extremely urgent problem especially for regions with a cold climate. HS system working on the effect of absorption and rejection of heat during the solid-liquid phase change of HS material is realised, tested and results of R and D are discussed. Numerical modelling was performed to calculate the HS mass-dimensional parameters. In the experimental part of the paper results of experiments on the pre-heating device to start a carburettor engine and analysis of data received are given. There is a good correlation between the experimental data and the results of numerical modelling of HS system functioning. (author)

  8. Thermal energy storage for electricity-driven space heating in a day-ahead electricity market

    DEFF Research Database (Denmark)

    Pensini, Alessandro

    2012-01-01

    Thermal Energy Storage (TES) in a space heating (SH) application was investigated. The study aimed to determine the economic benefits of introducing TES into an electricity-driven SH system under a day-ahead electricity market. The performance of the TES was assessed by comparing the cost...... of electricity in a system with a TES unit to the case where no storage is in use and the entire heat requirement is fulfilled by purchasing electricity according to the actual load. The study had two goals: 1. Determining how the size – in terms of electricity input (Pmax) and energy capacity (Emax......) – of the TES unit influences the savings. For this purpose, a reference price signal was used. Results show that it is possible to save up to approximately 14% of the electricity costs. In general, savings increase with Pmax and Emax. However, the benefit of increasing these two values ceases when certain...

  9. Heat exchange studies on coconut oil cells as thermal energy storage for room thermal conditioning

    Science.gov (United States)

    Sutjahja, I. M.; Putri, Widya A.; Fahmi, Z.; Wonorahardjo, S.; Kurnia, D.

    2017-07-01

    As reported by many thermal environment experts, room air conditioning might be controlled by thermal mass system. In this paper we discuss the performance of coconut oil cells as room thermal energy storage. The heat exchange mechanism of coconut oil (CO) which is one of potential organic Phase Change Material (PCM) is studied based on the results of temperature measurements in the perimeter and core parts of cells. We found that the heat exchange performance, i.e. heat absorption and heat release processes of CO cells are dominated by heat conduction in the sensible solid from the higher temperature perimeter part to the lower temperature core part and heat convection during the solid-liquid phase transition and sensible liquid phase. The capability of heat absorption as measured by the reduction of air temperature is not influenced by CO cell size. Besides that, the application of CO as the thermal mass has to be accompanied by air circulation to get the cool sensation of the room’s occupants.

  10. Solar passive ceiling system. Final report. [Passive solar heating system with venetian blind reflectors and latent heat storage in ceiling

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.R.

    1980-01-01

    The construction of a 1200 square foot building, with full basement, built to be used as a branch library in a rural area is described. The primary heating source is a passive solar system consisting of a south facing window system. The system consists of: a set of windows located in the south facing wall only, composed of double glazed units; a set of reflectors mounted in each window which reflects sunlight up to the ceiling (the reflectors are similar to venetian blinds); a storage area in the ceiling which absorbs the heat from the reflected sunlight and stores it in foil salt pouches laid in the ceiling; and an automated curtain which automatically covers and uncovers the south facing window system. The system is totally passive and uses no blowers, pumps or other active types of heat distribution equipment. The building contains a basement which is normally not heated, and the north facing wall is bermed four feet high around the north side.

  11. Thermal energy storage for building heating and cooling applications. Quarterly progress report, April--June 1976

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, H.W.; Kedl, R.J.

    1976-11-01

    This is the first in a series of quarterly progress reports covering activities at ORNL to develop thermal energy storage (TES) technology applicable to building heating and cooling. Studies to be carried out will emphasize latent heat storage in that sensible heat storage is held to be an essentially existing technology. Development of a time-dependent analytical model of a TES system charged with a phase-change material was started. A report on TES subsystems for application to solar energy sources is nearing completion. Studies into the physical chemistry of TES materials were initiated. Preliminary data were obtained on the melt-freeze cycle behavior and viscosities of sodium thiosulfate pentahydrate and a mixture of Glauber's salt and Borax; limited melt-freeze data were obtained on two paraffin waxes. A subcontract was signed with Monsanto Research Corporation for studies on form-stable crystalline polymer pellets for TES; subcontracts are being negotiated with four other organizations (Clemson University, Dow Chemical Company, Franklin Institute, and Suntek Research Associates). Review of 10 of 13 unsolicited proposals received was completed by the end of June 1976.

  12. Numerical simulations of the impact of seasonal heat storage on source zone emission in a TCE contaminated aquifer

    Science.gov (United States)

    Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

    2016-04-01

    In urban regions, with high population densities and heat demand, seasonal high temperature heat storage in the shallow subsurface represents an attractive and efficient option for a sustainable heat supply. In fact, the major fraction of energy consumed in German households is used for room heating and hot water production. Especially in urbanized areas, however, the installation of high temperature heat storage systems is currently restricted due to concerns on negative influences on groundwater quality caused e.g. by possible interactions between heat storages and subsurface contaminants, which are a common problem in the urban subsurface. Detailed studies on the overall impact of the operation of high temperature heat storages on groundwater quality are scarce. Therefore, this work investigates possible interactions between groundwater temperature changes induced by heat storage via borehole heat exchangers and subsurface contaminations by numerical scenario analysis. For the simulation of non-isothermal groundwater flow, and reactive transport processes the OpenGeoSys code is used. A 2D horizontal cross section of a shallow groundwater aquifer is assumed in the simulated scenario, consisting of a sandy sediment typical for Northern Germany. Within the aquifer a residual trichloroethene (TCE) contaminant source zone is present. Temperature changes are induced by a seasonal heat storage placed within the aquifer with scenarios of maximum temperatures of 20°C, 40°C and 60°C, respectively, during heat injection and minimum temperatures of 2°C during heat extraction. In the scenario analysis also the location of the heat storage relative to the TCE source zone and plume was modified. Simulations were performed in a homogeneous aquifer as well as in a set of heterogeneous aquifers with hydraulic conductivity as spatially correlated random fields. In both cases, results show that the temperature increase in the heat plume and the consequential reduction of water

  13. Experimental and numerical investigations of a small scale double-reflector concentrating solar system with latent heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Woh, Foong Chee

    2011-07-01

    The main aim of this doctoral thesis is to analyze a small scale double- reflector concentrating solar system with latent heat storage in temperature range 230 to 250 Celsius so that cooking can be done efficiently and effectively in the late evening or at night time. Many solar heat collection systems are based on transportation of heat from the focal point to the storage by a circulating heat transfer fluid. In this study, double-reflector arrangement is designed and tested to heat up the thermal heat storage directly without using any heat transport fluid. This makes the system more simple and easy to fabricate. NaNO3-KNO3 binary mixture is selected as the latent heat storage medium because the melting temperature of around 220 Celsius is in a suitable range.There are several objectives in this study. First of all, characterization of phase change materials has been carried out using differential scanning calorimeter (DSC). Important information such as heat capacity as a function of temperature, melting temperature, solid-solid phase transition temperature, enthalpy of fusion, and enthalpy of solid-solid phase transition can be obtained and used in the phase change numerical simulations.After the characterization and selection of a phase change material, a double-reflector system with thermal energy storage was designed and constructed. In order to test the concept of the design, a reflection system using laser diode technique was used in a smoke chamber. Focal point of the primary reflector was determined experimentally and compared with the theoretical calculations. The latent heat storage unit was filled with the NaNO3-KNO3 binary mixture until 90% full. Copper top plate and fin was used to increase the heat transfer rate into the phase change material. With the double-reflector system, thermal charging of the heat storage was carried out under the sun.Numerical simulations of the thermal charging process have been done using finite element model from COMSOL

  14. Thermochemical Characterizations of Novel Vermiculite-LiCl Composite Sorbents for Low-Temperature Heat Storage

    Directory of Open Access Journals (Sweden)

    Yannan Zhang

    2016-10-01

    Full Text Available To store low-temperature heat below 100 °C, novel composite sorbents were developed by impregnating LiCl into expanded vermiculite (EVM in this study. Five kinds of composite sorbents were prepared using different salt concentrations, and the optimal sorbent for application was selected by comparing both the sorption characteristics and energy storage density. Textural properties of composite sorbents were obtained by extreme-resolution field emission scanning electron microscopy (ER-SEM and an automatic mercury porosimeter. After excluding two composite sorbents which would possibly exhibit solution leakage in practical thermal energy storage (TES system, thermochemical characterizations were implemented through simulative sorption experiments at 30 °C and 60% RH. Analyses of thermogravimetric analysis/differential scanning calorimetry (TGA/DSC curves indicate that water uptake of EVM/LiCl composite sorbents is divided into three parts: physical adsorption of EVM, chemical adsorption of LiCl crystal, and liquid–gas absorption of LiCl solution. Energy storage potential was evaluated by theoretical calculation based on TGA/DSC curves. Overall, EVMLiCl20 was selected as the optimal composite sorbent with water uptake of 1.41 g/g, mass energy storage density of 1.21 kWh/kg, and volume energy storage density of 171.61 kWh/m3.

  15. Prototyping Energy Efficient Thermo-Magnetic & Induction Hardening for Heat Treat & Net Shape Forming Applications

    Energy Technology Data Exchange (ETDEWEB)

    Aquil Ahmad

    2012-08-03

    Within this project, Eaton undertook the task of bringing about significant impact with respect to sustainability. One of the major goals for the Department of Energy is to achieve energy savings with a corresponding reduction in carbon foot print. The use of a coupled induction heat treatment with high magnetic field heat treatment makes possible not only improved performance alloys, but with faster processing times and lower processing energy, as well. With this technology, substitution of lower cost alloys for more exotic alloys became a possibility; microstructure could be tailored for improved magnetic properties or wear resistance or mechanical performance, as needed. A prototype commercial unit has been developed to conduct processing of materials. Testing of this equipment has been conducted and results demonstrate the feasibility for industrial commercialization.

  16. Freestanding, heat resistant microporous film for use in energy storage devices

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, Richard W.; Cherukupalli, Srinivas; Waterhouse, Robert R.

    2018-02-20

    Preferred embodiments of a freestanding, heat resistant microporous polymer film (10) constructed for use in an energy storage device (70, 100) implements one or more of the following approaches to exhibit excellent high temperature mechanical and dimensional stability: incorporation into a porous polyolefin film of sufficiently high loading levels of inorganic or ceramic filler material (16) to maintain porosity (18) and achieve low thermal shrinkage; use of crosslinkable polyethylene to contribute to crosslinking the polymer matrix (14) in a highly inorganic material-filled polyolefin film; and heat treating or annealing of biaxially oriented, highly inorganic material-filled polyolefin film above the melting point temperature of the polymer matrix to reduce residual stress while maintaining high porosity. The freestanding, heat resistant microporous polymer film embodiments exhibit extremely low resistance, as evidenced by MacMullin numbers of less than 4.5.

  17. Experimental analysis of the performance of optimized fin structures in a latent heat energy storage test rig

    Science.gov (United States)

    Johnson, Maike; Hübner, Stefan; Reichmann, Carsten; Schönberger, Manfred; Fiß, Michael

    2017-06-01

    Energy storage systems are a key technology for developing a more sustainable energy supply system and lowering overall CO2 emissions. Among the variety of storage technologies, high temperature phase change material (PCM) storage is a promising option with a wide range of applications. PCM storages using an extended finned tube storage concept have been designed and techno-economically optimized for solar thermal power plant operations. These finned tube components were experimentally tested in order to validate the optimized design and simulation models used. Analysis of the charging and discharging characteristics of the storage at the pilot scale gives insight into the heat distribution both axially as well as radially in the storage material, thereby allowing for a realistic validation of the design. The design was optimized for discharging of the storage, as this is the more critical operation mode in power plant applications. The data show good agreement between the model and the experiments for discharging.

  18. Recent wind-driven change in Subantarctic Mode Water and its impact on ocean heat storage

    Science.gov (United States)

    Gao, Libao; Rintoul, Stephen R.; Yu, Weidong

    2018-01-01

    The subduction and export of Subantarctic Mode Water (SAMW) supplies the upper limb of the overturning circulation and makes an important contribution to global heat, freshwater, carbon and nutrient budgets1-5. Upper ocean heat content has increased since 2006, helping to explain the so-called global warming hiatus between 1998 and 2014, with much of the ocean warming concentrated in extratropical latitudes of the Southern Hemisphere in close association with SAMW and Antarctic Intermediate Water (AAIW)6,7. Here we use Argo observations to assess changes in the thickness, depth and heat content of the SAMW layer. Between 2005 and 2015, SAMW has thickened (3.6 ± 0.3 m yr-1), deepened (2.4 ± 0.2 m yr-1) and warmed (3.9 ± 0.3 W m-2). Wind forcing, rather than buoyancy forcing, is largely responsible for the observed trends in SAMW. Most (84%) of the increase in SAMW heat content is the result of changes in thickness; warming by buoyancy forcing (increased heat flux to the ocean) accounts for the remaining 16%. Projected increases in wind stress curl would drive further deepening of SAMW and increase in heat storage in the Southern Hemisphere oceans.

  19. Advice on Sustainable Use of the Underground for Heat and Cold Storage; Advies Duurzaam Gebruik van de Bodem voor WKO

    Energy Technology Data Exchange (ETDEWEB)

    Oomes, J.

    2009-09-15

    Insights and ideas are given and discussed with regard to sustainable use of soil and underground for heat and cold storage. Also attention is paid to the marginal conditions for the application of heat and cold storage [Dutch] Inzichten en ideeen worden gegeven en besproken over duurzaam gebruik van de bodem voor warmte- koudeopslag (WKO). Daarnaast worden ook de randvoorwaarden van WKO in kaart gebracht.

  20. Solar district heating and seasonal heat storage - state of the art; Solare Nahwaerme und Saisonale Waermespeicherung - Stand der Technik

    Energy Technology Data Exchange (ETDEWEB)

    Pfeil, M.; Hahne, E. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany). Geschaeftsbereich Solarthermische Energietechnik; Lottner, V. [BEO Biologie, Energie Oekologie, Juelich (Germany); Schulz, M. [Stuttgart Univ. (Germany). Inst. fuer Thermodynamik und Waermetechnik

    1998-02-01

    Solar energy technology becomes more and more important for space and water heating of residential buildings. Compared to small systems for single-family houses, the specific investment cost of big solar plants is lower and a higher contribution of solar energy can be achieved. In central solar heating plants with seasonal storage (CSHPSS), more than 50% of the total heat demand of residential areas can be covered by solar energy. The first pilot plants for CSHPSS are operating in Germany since 1996. The first results of the accompanying monitoring program show good agreement between calculated and actual solar contribution. (orig.) [Deutsch] Die Nutzung solarer Niedertemperaturwaerme zur Brauchwassererwaermung und zur Beheizung von Wohngebaeuden erfaehrt in Deutschland ein immer groesseres Interesse. Solare Grossanlagen haben gegenueber solaren Kleinanlagen den Vorteil, dass mit geringeren Investitions- und Waermekosten groessere Anlagenertraege erzielt werden koennen. In Verbindung mit saisonaler Waermespeicherung erreichen solare Grossanlagen Deckungsanteile von 50% und darueber am Gesamtwaermebedarf von Wohnsiedlungen. Die ersten Pilotanlagen zur solaren Nahwaerme mit saisonalem Waermespeicher gingen 1996 in Betrieb und werden derzeit detailliert vermessen. Erste Ergebnisse zeigen, dass die vorausberechneten Werte fuer den Jahresenergieertrag erreicht werden koennen. (orig.)

  1. Solar Sustainable Heating, Cooling and Ventilation of a Net Zero Energy House

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Skrupskelis, Martynas; Olesen, Bjarne W.

    Present work addresses the heating, cooling and ventilation concerns of the Technical University of Denmark’s house, Fold, for Solar Decathlon Europe 2012. Various innovative approaches are investigated, namely, utilization of ground, photo-voltaic/thermal (PV/T) panels and phase change materials...... by the embedded pipes which are coupled with the ground. Ventilation is mainly used to control the humidity and to remove sensory and chemical pollution. PV/T panels enable the house to be a “plus” energy house. PV/T also yields to a solar fraction of 63% and 31% for Madrid and Copenhagen, respectively...

  2. Thermal energy storage in the form of heat or cold with using of the PCM-based accumulation panels

    Directory of Open Access Journals (Sweden)

    Skovajsa Jan

    2016-01-01

    Full Text Available This article describes the usage of thermal energy storage in the form of heat and cold with an adaptation of the special device which is composed of the thermal panels. These panels are based on the phase change materials (PCM for normal inner environment temperature in buildings. The energy for the thermal energy storage is possible to get from built-in electric heating foil or from the tube heat exchanger, which is build in the thermal panels. This technology is able to use renewable energy sources, for example, solar thermal collectors and air-to-water heat pump as a source of heat for heating of the hot water tank. In the cooling mode, there is able to use the heat pump or photovoltaics panels in combination with thermoelectric coolers for cooling.

  3. Effect of Harvest Maturity and Heat Pretreatment on the Quality of Low Temperature Storage Avocados in Taiwan

    OpenAIRE

    Wu, Chun-Ta; Roan, Su-Feng; Hsiung, Tung-Chuan; Chen, Iou-Zen; Shyr, Jeng-Jung; Wakana, Akira; 若菜, 章

    2011-01-01

    The present study aimed to find out the effects of different fruit maturities and heat pretreatments before storage on the quality of climacteric avocado fruit during low temperature storage. Two local cultivars, 'Chanan' and 'Ching?Jin 2', were chosen to analyze the relationship between the degree of fruit maturity at harvest and the quality of the fruits after low temperature (1℃) storage. Quality changes were observed in terms of color of skin, color of flesh, fruit hardiness, chilling inj...

  4. Phase change behaviour of some latent heat storage media based on calcium chloride hexahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Bo [School of Pure and Applied Natural Sciences, University of Kalmar, SE-39182 Kalmar (Sweden)

    2009-04-15

    Phase change behaviour of pure and some chemically modified calcium chloride hexahydrate materials suggested in the literature as suitable heat storage media was studied in storage systems with a low degree of mixing in order to evaluate their long-term reversibility. The influence of gravitation on the phase change properties of the pure system was elaborated by determining local salt concentrations in the liquid phase and changes in the volume of the system during repeated melting and crystallization, whereby the amounts of the different phases being present could be assessed. It was found that thermo gravitational effects are of minor importance in generating salt concentration gradients in the liquid phase when compared to the concentration gradients resulting from the sedimentation of the formed tetrahydrate and the hexahydrate during the phase change reactions. Due to these effects it was not possible to prevent irreversible tetrahydrate formation and deterioration in heat storage capability by adding a surplus of water to the hexahydrate materials, if seeds for the tetrahydrate were present during repeated melting and crystallization. Upon addition of SrCl{sub 2} . 6H{sub 2}O a solid solution of the two hexahydrates is formed and as a result the formation of the tetrahydrate is suppressed. Due to irreversible formation of SrCl{sub 2} . 2H{sub 2}O a state of true congruent melting seems, however, not possible to reach. Phase segregation effects also in this case lead to irreversible calcium chloride tetrahydrate formation if seeds for the latter are added during repeated melting and crystallization. If Ca(OH){sub 2} is also added, the tetrahydrate formation can be further suppressed. But, even in this case, irreversible tetrahydrate formation can not be prevented if the composition of the liquid phase corresponds to the hexahydrate. On addition of 5 wt% KCl or 5 wt% KCl + 2 wt% SrCl{sub 2} . 6H{sub 2}O or 5 wt% KCl + 0.4 wt% NaCl, repeated melting and

  5. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms.

    Science.gov (United States)

    Rowe, M F; Bakken, G S; Ratliff, J J; Langman, V A

    2013-05-15

    Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity.

  6. Novel metallic alloys as phase change materials for heat storage in direct steam generation applications

    Science.gov (United States)

    Nieto-Maestre, J.; Iparraguirre-Torres, I.; Velasco, Z. Amondarain; Kaltzakorta, I.; Zubieta, M. Merchan

    2016-05-01

    Concentrating Solar Power (CSP) is one of the key electricity production renewable energy technologies with a clear distinguishing advantage: the possibility to store the heat generated during the sunny periods, turning it into a dispatchable technology. Current CSP Plants use an intermediate Heat Transfer Fluid (HTF), thermal oil or inorganic salt, to transfer heat from the Solar Field (SF) either to the heat exchanger (HX) unit to produce high pressure steam that can be leaded to a turbine for electricity production, or to the Thermal Energy Storage (TES) system. In recent years, a novel CSP technology is attracting great interest: Direct Steam Generation (DSG). The direct use of water/steam as HTF would lead to lower investment costs for CSP Plants by the suppression of the HX unit. Moreover, water is more environmentally friendly than thermal oils or salts, not flammable and compatible with container materials (pipes, tanks). However, this technology also has some important challenges, being one of the major the need for optimized TES systems. In DSG, from the exergy point of view, optimized TES systems based on two sensible heat TES systems (for preheating of water and superheating vapour) and a latent heat TES system for the evaporation of water (around the 70% of energy) is the preferred solution. This concept has been extensively tested [1, 2, 3] using mainly NaNO3 as latent heat storage medium. Its interesting melting temperature (Tm) of 306°C, considering a driving temperature difference of 10°C, means TES charging steam conditions of 107 bar at 316°C and discharging conditions of 81bar at 296°C. The average value for the heat of fusion (ΔHf) of NaNO3 from literature data is 178 J/g [4]. The main disadvantage of inorganic salts is their very low thermal conductivity (0.5 W/m.K) requiring sophisticated heat exchanging designs. The use of high thermal conductivity eutectic metal alloys has been recently proposed [5, 6, 7] as a feasible alternative. Tms

  7. Experimental Study of Thermal Energy Storage Characteristics using Heat Pipe with Nano-Enhanced Phase Change Materials

    Science.gov (United States)

    Krishna, Jogi; Kishore, P. S.; Brusly Solomon, A.

    2017-08-01

    The paper presents experimental investigations to evaluate thermal performance of heat pipe using Nano Enhanced Phase Change Material (NEPCM) as an energy storage material (ESM) for electronic cooling applications. Water, Tricosane and nano enhanced Tricosane are used as energy storage materials, operating at different heating powers (13W, 18W and 23W) and fan speeds (3.4V and 5V) in the PCM cooling module. Three different volume percentages (0.5%, 1% and 2%) of Nano particles (Al2O3) are mixed with Tricosane which is the primary PCM. This experiment is conducted to study the temperature distributions of evaporator, condenser and PCM during the heating as well as cooling. The cooling module with heat pipe and nano enhanced Tricosane as energy storage material found to save higher fan power consumption compared to the cooling module that utilities only a heat pipe.

  8. Design and Testing of a Thermal Storage System for Electric Vehicle Cabin Heating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyu [MAHLE Behr Troy Inc.; WolfeIV, Edward [MAHLE Behr Troy Inc.; Craig, Timothy [MAHLE Behr Troy Inc.; LaClair, Tim J [ORNL; Gao, Zhiming [ORNL; Abdelaziz, Omar [ORNL

    2016-01-01

    Without the waste heat available from the engine of a conventional automobile, electric vehicles (EVs) must provide heat to the cabin for climate control using energy stored in the vehicle. In current EV designs, this energy is typically provided by the traction battery. In very cold climatic conditions, the power required to heat the EV cabin can be of a similar magnitude to that required for propulsion of the vehicle. As a result, the driving range of an EV can be reduced very significantly during winter months, which limits consumer acceptance of EVs and results in increased battery costs to achieve a minimum range while ensuring comfort to the EV driver. To minimize the range penalty associated with EV cabin heating, a novel climate control system that includes thermal energy storage has been designed for use in EVs and plug-in hybrid electric vehicles (PHEVs). The system uses the stored latent heat of an advanced phase change material (PCM) to provide cabin heating. The PCM is melted while the EV is connected to the electric grid for charging of the electric battery, and the stored energy is subsequently transferred to the cabin during driving. To minimize thermal losses when the EV is parked for extended periods, the PCM is encased in a high performance insulation system. The electrical PCM-Assisted Thermal Heating System (ePATHS) was designed to provide enough thermal energy to heat the EV s cabin for approximately 46 minutes, covering the entire daily commute of a typical driver in the U.S.

  9. Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

    Science.gov (United States)

    Milkus, Chri(Sch)augott

    2015-04-01

    Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

  10. Optimum efficiencies and phase change temperatures in latent heat storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Aceves-Saborio, S.; Nakamura, H. (Daido Inst. of Tech., Nagoya (Japan). Dept. of Mechanical Engineering); Reistad, G.M. (Oregon State Univ., Corvallis, OR (United States). Dept. of Mechanical Engineering)

    1994-03-01

    This paper presents an analysis of a class of latent heat storage systems (LHSS). The analysis is based on a lumped model (the basic model) that allows a broad class of LHSSs to be completely specified, with only two parameters and a set of operating temperatures, while still retaining the main thermodynamic aspects associated with its operation. Characterization of the performance in this manner permits the broad base application potential of such systems to be viewed. This modeling is in contrast to most studies to date, which employ many parameters to include details of specific systems, and therefore obscure, to a great extent, this broad-based application potential. The basic model is later modified in three ways to analyze operating conditions that either occur in practical units or are desirable for an improved operation of the units. The modifications include, first, the consideration of the LHSS as being formed by many independent phase-change material (PCM) capsules. Second, the possibility of having PCMs with different phase change temperatures filling the capsules. Third, the case when the PCM melts over a temperature range. The results indicate that the efficiency of the basic model represents a higher bound for the efficient operation of LHSSs with negligible sensible storage capacity, and a single PCM. Using multiple PCMs within a LHSS results in higher efficiencies. These efficiencies set higher bounds for efficiency of any sensible or latent heat storage system, and also represent the only possibility for reversible operation of LHSS.

  11. Accumulation of plant small heat-stress proteins in storage organs.

    Science.gov (United States)

    Lubaretz, Olga; Zur Nieden, Uta

    2002-06-01

    Plant small heat-stress proteins (sHSPs) have been shown to be expressed not only after exposure to elevated temperatures, but also at particular developmental stages such as embryogenesis, microsporogenesis, and fruit maturation. This paper presents new data on the occurrence of sHSPs in vegetative tissues, their tissue-specific distribution, and cellular localization. We have found sHSPs in 1-year-old twigs of Acer platanoides L. and Sambucus nigra L. and in the liana Aristolochia macrophylla Lamk. exclusively in the winter months. In tendrils of Aristolochia, sHSPs were localized in vascular cambium cells. After budding, in spring, these proteins were no longer present. Furthermore, accumulation of sHSPs was demonstrated in tubers and bulbs of Allium cepa L., Amaryllis ( Hippeastrum hybridum hort.), Crocus albiflorus L., Hyacinthus orientalis L., Narcissus pseudonarcissus L., Tulipa gesneriana L., and Solanum tuberosum L. (potato). In potato tubers and bulb scales of Narcissus the stress proteins were localized in the central vacuoles of storage parenchyma cells. In order to obtain more information on a possible functional correlation between storage proteins and sHSPs, the accumulation of both types of protein in tobacco seeds during seed ripening and germination was monitored. The expression of sHSPs and globulins started simultaneously at about the 17th day after anthesis. During seed germination the sHSPs disappeared in parallel with the storage proteins. Furthermore, in embryos of transgenic tobacco plants, which do not contain any protein bodies or storage proteins, no sHSPs were found. Thus, the occurrence of sHSPs in perennial plant storage organs seems to be associated with the presence of storage proteins.

  12. Coupled Simulation of Borehole Thermal Energy Storages and Solar District Heating Systems

    Science.gov (United States)

    Formhals, Julian; Schulte, Daniel O.; Welsch, Bastian; Sass, Ingo

    2017-04-01

    The temporal difference between times of high heat demands and times of high solar heat supplies can be compensated by solar district heating (SDH) with borehole thermal energy storage (BTES) systems. To achieve a good understanding of the system behavior and for optimized dimensioning of the components transient simulations are imperative. In this context the models of SDH systems and BTES pose very different requirements on their simulation environments. Taking this into account, a coupled simulation, in which both models can be realized in separate and specialized simulation environments becomes favorable. The underlying work presents a new approach for a coupled simulation of a SDH system modelled in SimulationX and a BTES system modelled in MATLAB. A case study is performed, in which a SDH system with an annual heat demand of 1,100 MWh and a BTES is designed and dimensioned. The SDH is modelled in SimulationX and later coupled to an existing model of a BTES in MATLAB. Subsequently, a simulation over seven years is carried out to assess the performance of the designed system and the presented coupling method. For the designed system, a storage efficiency of 56.6% and a solar fraction of 36.6% can be achieved after the final year. The implementation of a heat pump proves to be beneficial for the performance of the system. A detailed analysis of the system and component behavior is performed, which concludes in a good understanding of interdependencies between the components and the identification of potential improvements. Following this, an improvement strategy for the system is developed, in which major potentials are related to a more sophisticated control strategy.

  13. Heat storage in underground caverns - measurements and simulations; Speicherung von Waerme in Grubenraeumen - Messung und Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Schaberg, A.; Krause, H.; Poetke, W. [TU Bergakademie Freiberg (Germany). Inst. fuer Waermetechnik und Technische Thermodynamik

    1997-12-01

    Among the different discussed underground concepts for longterm storing of solar or waste heat old waterfilled mines can be an interesting solution. To examine the temperature behaviour of this storage type a testing store is built in a mine belonging to the Freiberg University of Mining and Technology in Saxonia. In a longterm project temperatures are measured inside the water volume and in the adjacent rock. The temperature behaviour depends on the operating conditions. Inside the water volume temperature stratification can be observed. During loading and standstill heat is transported into the rock surrounding. A certain part of this amount of heat can be discharged again. For designing and optimizing this storage type a numerical modell is developed. The modell is validated with experimental data from the testing plant. (orig.) [Deutsch] Unter den verschiedenen, in der Diskussion stehenden Untegrund-Waermespeichern fuer Solarwaerme oder Abwaerme bieten sich auch geflutete Gruben als Waermespeicher an. Zur Untersuchung des Temperaturverhaltens dieses Speichertyps ist im Saechsischen Lehr- und Besucherbergwerk der TU Bergakademie Freiberg ein Versuchsspeicher errichtet worden. In einem Langzeitversuch wird das Temperaturfeld im Wasser und im angrenzenden Gestein aufgezeichnet. Das Temperaturverhalten ist von den Betriebsgroessen abhaengig. Im Grubenwasser stellt sich eine stabile Temperaturschichtung ein. Waehrend der Beladung und der Stillstandszeiten wird Waerme in die Gesteinsumgebung transportiert. Ein Teil dieser Waermemenge kann wider entspeichert werden. Zur Auslegung und Optimierung von Gruben-Waermespeichern ist ein numerisches Modell entwickelt worden. Das Modell ist anhand der Messergebnisse des Versuchsspeichers validiert worden. (orig.)

  14. FY 17 Q1 Commercial integrated heat pump with thermal storage milestone report

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Heiba, Ahmad [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-01

    The commercial integrated heat pump with thermal storage (AS-IHP) offers significant energy saving over a baseline heat pump with electric water heater. The saving potential is maximized when the AS-IHP serves coincident high water heating and high space cooling demands. A previous energy performance analysis showed that the AS-IHP provides the highest benefit in the hot-humid and hot-dry/mixed dry climate regions. Analysis of technical potential energy savings for these climate zones based on the BTO Market calculator indicated that the following commercial building market segments had the highest water heating loads relative to space cooling and heating loads education, food service, health care, lodging, and mercantile/service. In this study, we focused on these building types to conservatively estimate the market potential of the AS-IHP. Our analysis estimates maximum annual shipments of ~522,000 units assuming 100% of the total market is captured. An early replacement market based on replacement of systems in target buildings between 15 and 35 years old was estimated at ~136,000 units. Technical potential energy savings are estimated at ~0.27 quad based on the maximum market estimate, equivalent to ~13.9 MM Ton CO2 emissions reduction.

  15. Numerical analysis of latent heat storage system with encapsulated phase change material in spherical capsules

    Directory of Open Access Journals (Sweden)

    Bellan Selvan

    2017-01-01

    Full Text Available Solar energy has been considered as one of the promising solutions to replace the fossil fuels. To generate electricity beyond normal daylight hours, thermal energy storage systems (TES play a vital role in concentrated solar power (CSP plants. Thus, a significant focus has been given on the improvement of TES systems from the past few decades. In this study, a numerical model is developed to obtain the detailed heat transfer characteristics of lab-scale latent thermal energy storage system, which consists of molten salt encapsulated spherical capsules and air. The melting process and the corresponding temperature and velocity distributions in every capsule of the system are predicted. The enthalpy-porosity approach is used to model the phase change region. The model is validated with the reported experimental results. Influence of initial condition on the thermal performance of the TES system is predicted.

  16. Experimental investigation on AC unit integrated with sensible heat storage (SHS)

    Science.gov (United States)

    Aziz, N. A.; Amin, N. A. M.; Majid, M. S. A.; Hussin, A.; Zhubir, S.

    2017-10-01

    The growth in population and economy has increases the energy demand and raises the concerns over the sustainable energy source. Towards the sustainable development, energy efficiency in buildings has become a prime objective. In this paper, the integration of thermal energy storage was studied. This paper presents an experimental investigation on the performance of an air conditioning unit integrated with sensible heat storage (SHS) system. The results were compared to the conventional AC systems in the terms of average electricity usage, indoor temperature and the relative humidity inside the experimented room (cabin container). Results show that the integration of water tank as an SHS reduces the electricity usage by 5%, while the integration of well-insulated water tank saves up to 8% of the electricity consumption.

  17. Automatic control of electric thermal storage (heat) under real-time pricing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Daryanian, B.; Tabors, R.D.; Bohn, R.E. [Tabors Caramanis and Associates, Inc. (United States)

    1995-01-01

    Real-time pricing (RTP) can be used by electric utilities as a control signal for responsive demand-side management (DSM) programs. Electric thermal storage (ETS) systems in buildings provide the inherent flexibility needed to take advantage of variations in prices. Under RTP, optimal performance for ETS operations is achieved under market conditions where reductions in customers` costs coincide with the lowering of the cost of service for electric utilities. The RTP signal conveys the time-varying actual marginal cost of the electric service to customers. The RTP rate is a combination of various cost components, including marginal generation fuel and maintenance costs, marginal costs of transmission and distribution losses, and marginal quality of supply and transmission costs. This report describes the results of an experiment in automatic control of heat storage systems under RTP during the winter seasons of 1989--90 and 1990--91.

  18. Thermal performance evaluation of a latent heat storage unit for late evening cooking in a solar cooker having three reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Buddhi, D.; Sharma, A. [Devi Ahilya University, Indore (India). School of Energy and Environmental Studies, Thermal Energy Storage Laboratory; Sharma, S.D. [Mie University, Tsu (Japan). Faculty of Engineering, Department of Architecture

    2003-04-01

    In this paper, a phase change material (PCM) storage unit for a solar cooker was designed and developed to store energy during sunshine hours. The stored energy was utilised to cook food in the late evening. Commercial grade acetanilide (melting point 118.9 {sup o}C, latent heat of fusion 222 kJ/kg) was used as a latent heat storage material. Evening cooking experiments were conducted with different loads and loading times during the winter season. The experimental results showed that late evening cooking is possible in a solar cooker having three reflectors to enhance the incident solar radiation with the PCM storage unit. (author)

  19. Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

    Science.gov (United States)

    Ternovykh, Mikhail; Tikhomirov, Georgy; Saldikov, Ivan; Gerasimov, Alexander

    2017-09-01

    Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 105 years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of 244Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.

  20. Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

    Directory of Open Access Journals (Sweden)

    Ternovykh Mikhail

    2017-01-01

    Full Text Available Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 105 years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of 244Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.

  1. Net Greenhouse Gas Budget and Soil Carbon Storage in a Field with Paddy–Upland Rotation with Different History of Manure Application

    Directory of Open Access Journals (Sweden)

    Fumiaki Takakai

    2017-06-01

    Full Text Available Methane (CH4 and nitrous oxide (N2O fluxes were measured from paddy–upland rotation (three years for soybean and three years for rice with different soil fertility due to preceding compost application for four years (i.e., 3 kg FW m−2 year−1 of immature or mature compost application plots and a control plot without compost. Net greenhouse gas (GHG balance was evaluated by integrating CH4 and N2O emissions and carbon dioxide (CO2 emissions calculated from a decline in soil carbon storage. N2O emissions from the soybean upland tended to be higher in the immature compost plot. CH4 emissions from the rice paddy increased every year and tended to be higher in the mature compost plot. Fifty-two to 68% of the increased soil carbon by preceding compost application was estimated to be lost during soybean cultivation. The major component of net GHG emission was CO2 (82–94% and CH4 (72–84% during the soybean and rice cultivations, respectively. Net GHG emissions during the soybean and rice cultivations were comparable. Consequently, the effects of compost application on the net GHG balance from the paddy–upland rotation should be carefully evaluated with regards to both advantages (initial input to the soil and disadvantages (following increases in GHG.

  2. The integration of water loop heat pump and building structural thermal storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Marseille, T.J.; Schliesing, J.S.

    1991-10-01

    Many commercial buildings need heat in one part and, at the same time, cooling in another part. Even more common is the need for heating during one part of the day and cooling during another in the same spaces. If that energy could be shifted or stored for later use, significant energy might be saved. If a building's heating and cooling subsystems could be integrated with the building's structural mass and used to collect, store, and deliver energy, the energy might be save cost-effectively. To explore this opportunity, researchers at the Pacific Northwest Laboratory (PNL) examined the thermal interactions between the heating, ventilating, and air-conditioning (HVAC) system and the structure of a commercial building. Computer models were developed to simulate the interactions in an existing building located in Seattle, Washington, to determine how these building subsystems could be integrated to improve energy efficiency. The HVAC subsystems in the existing building were modeled. These subsystems consist of decentralized water-source heat pumps (WSHP) in a closed water loop, connected to cooling towers for heat rejection during cooling mode and boilers to augment heating. An initial base case'' computer model of the Seattle building, as-built, was developed. Metered data available for the building were used to calibrate this model to ensure that the analysis would provide information that closely reflected the operation of a real building. The HVAC system and building structure were integrated in the model using the concrete floor slabs as thermal storage media. The slabs may be actively charged during off-peak periods with the chilled water in the loop and then either actively or passively discharged into the conditioned space during peak periods. 21 refs., 37 figs., 17 tabs.

  3. Geochemical implications of production and storage control by coupling a direct-use geothermal system with heat networks

    NARCIS (Netherlands)

    Daniilidis, Alexandros; Scholten, Tjardo; Hooghiem, Joram; Persis, Claudio De; Herber, Rien

    2017-01-01

    This paper outlines a method in which the heat production of a geothermal system is controlled in relation to the demand from a district-heating network. A model predictive control strategy is designed, which uses volume measurements in the storage tank, and predictions of the demand, to regulate

  4. Buffer storage of thermal energy using the reaction heat of the system calcium oxide/calcium hydroxide

    Science.gov (United States)

    Lehmann, B.

    1986-12-01

    The reaction heat of the system CaO/Ca(OH)2 was investigated as storage effect for thermal energy. The heat from the chemical system is used as a buffer facility for thermal energy, i.e., sensible heat is stored without thermal losses to the environment. In the forward reaction by adding water to the CaO, sensible heat is released, which can be used for heating houses or water, and for generation of steam for industrial purposes. The necessary heat to be fed to the Ca(OH)2 in order to run the reaction inversely can be supplied by solar collector, high temperature reactors, geothermal energy, or combustion of wastes. Heat at temperatures less than 450 C has to be furnished for the loading phase of the reaction. The discharging reaction delivers temperatures up to 400 C. A gas loop was designed, built, and operated to test this kind of heat storage. The quantities which determine the storage and release of energy were deduced and documented. Pressure drops and storage mass behavior are discussed.

  5. Thermochemical storage for CSP via redox structured reactors/heat exchangers: The RESTRUCTURE project

    Science.gov (United States)

    Karagiannakis, George; Pagkoura, Chrysoula; Konstandopoulos, Athanasios G.; Tescari, Stefania; Singh, Abhishek; Roeb, Martin; Lange, Matthias; Marcher, Johnny; Jové, Aleix; Prieto, Cristina; Rattenbury, Michael; Chasiotis, Andreas

    2017-06-01

    The present work provides an overview of activities performed in the framework of the EU-funded collaborative project RESTRUCTURE, the main goal of which was to develop and validate a compact structured reactor/heat exchanger for thermochemical storage driven by 2-step high temperature redox metal oxide cycles. The starting point of development path included redox materials qualification via both theoretical and lab-scale experimental studies. Most favorable compositions were cobalt oxide/alumina composites. Preparation of small-scale structured bodies included various approaches, ranging from perforated pellets to more sophisticated honeycomb geometries, fabricated by extrusion and coating. Proof-of-concept of the proposed novel reactor/heat exchanger was successfully validated in small-scale structures and the next step included scaling up of redox honeycombs production. Significant challenges were identified for the case of extruded full-size bodies and the final qualified approach related to preparation of cordierite substrates coated with cobalt oxide. The successful experimental evaluation of the pilot reactor/heat exchanger system constructed motivated the preliminary techno-economic evaluation of the proposed novel thermochemical energy storage concept. Taking into account experimental results, available technologies and standard design aspects a model for a 70.5 MWe CSP plant was defined. Estimated LCOE costs were calculated to be in the range of reference values for Combined Cycle Power Plants operated by natural gas. One of main cost contributors was the storage system itself, partially due to relatively high cost of cobalt oxide. This highlighted the need to identify less costly and equally efficient to cobalt oxide redox materials.

  6. Heat Storage and Energy Closure in Two Tropical Montane Forests in Hawaii

    Science.gov (United States)

    Mudd, R. G.; Giambelluca, T. W.; Huang, M.

    2012-12-01

    To date, eddy covariance observations of evapotranspiration (ET) in tropical rainforest ecosystems are limited and thorough assessments of such observations are rare. In this study, we present a detailed evaluation of eddy covariance data collected at two sites in Hawaii Volcanoes National Park, Hawaii, for a 34 month period to evaluate the importance of biomass and air heat storage to the energy balance and determine site specific energy closure characteristics. One site is located in a native Hawaiian tropical montane forest dominated by Metrosideros polymorpha (Nahuku), while the other is located in a nearby forest (Olaa) that has been partially invaded by strawberry guava (Psidium cattleianum). Vertical and radial distribution of all biomass components were evaluated from detailed stand surveys, biomass samples, allometric relationships, wood density, fresh to dry weight ratios of plant materials, and temperature measurements of stem biomass. Total fresh biomass was estimated to be 69.8 ± 11.7 kg m-2 and 75.9 ± 16.6 kg m-2 at Nahuku and Olaa, respectively, and the contribution of separate biomass components to energy closure were evaluated in detail. Despite statistically similar fresh biomass between stands, energy storage was found to be significantly greater at the forest site with P. cattleianum tree invasion (Olaa) than at the native forest stand (Nahuku). The difference was attributed to a higher proportion of smaller stems at Olaa, absorbing and releasing more heat for a given mass. Inclusion of biomass and air heat storage in the energy balance improved the relative energy closure, the slope of the linear regression (forced through the origin) of the sum of latent and sensible heat fluxes measured above the canopies for each 30-minute period from 0.767 to 0.805 at Nahuku and from 0.918 to 0.997 at Olaa. The mean absolute energy imbalance, the mean of the differences between the available energy and the sum of latent and sensible heat fluxes for each

  7. Direct-contact high-temperature thermal energy storage heat exchanger

    Science.gov (United States)

    Alario, J. P.; Brown, R.

    1983-09-01

    A 10 kWh scale model high temperature direct contact latent heat exchange thermal energy storage system was fabricated. A research program was structured in three separate phases: (1) the inspection and evaluation of the original hardware, which suffered extensive corrosion and damage in a previous experimental program; (2) redesign and fabrication of a modified system, and (3) detailed test evaluation. In phase 1, the design was modified to eliminate previous deficiencies. Phase 2 entailed component procurement and fabrication, system assembly, and instrumentation. The results for the design and fabrication phases of the program are presented.

  8. Parametric study of thermal storage containing rocks or fluid filled cans for solar heating and cooling, phase 2

    Science.gov (United States)

    Saha, H.

    1981-01-01

    The test data and an analysis of the heat transfer characteristics of a solar thermal energy storage bed utilizing water filled cans and standard bricks as energy storage medium are presented. This experimental investigation was initiated to find a usable heat intensive solar thermal storage device other than rock storage and water tank. Four different sizes of soup cans were stacked in a chamber in three different arrangements-vertical, horizontal, and random. Air is used as transfer medium for charging and discharge modes at three different mass flow rates and inlet air temperature respectively. These results are analyzed and compared, which show that a vertical stacking and medium size cans with Length/Diameter (L/D) ratio close to one have better average characteristics of heat transfer and pressure drop.

  9. Energy performance and economic evaluation of heat pump/organic rankine cycle system with sensible thermal storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...

  10. Energy Performance and Economic Evaluation of Heat Pump/Organic Rankine Cycle System with Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, C.; Dumont, O.; Nielsen, M. P.

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...

  11. Metabolic crosstalk between membrane and storage lipids facilitates heat stress management in Schizosaccharomyces pombe.

    Science.gov (United States)

    Péter, Mária; Glatz, Attila; Gudmann, Péter; Gombos, Imre; Török, Zsolt; Horváth, Ibolya; Vígh, László; Balogh, Gábor

    2017-01-01

    Cell membranes actively participate in stress sensing and signalling. Here we present the first in-depth lipidomic analysis to characterize alterations in the fission yeast Schizosaccharomyces pombe in response to mild heat stress (HS). The lipidome was assessed by a simple one-step methanolic extraction. Genetic manipulations that altered triglyceride (TG) content in the absence or presence of HS gave rise to distinct lipidomic fingerprints for S. pombe. Cells unable to produce TG demonstrated long-lasting growth arrest and enhanced signalling lipid generation. Our results reveal that metabolic crosstalk between membrane and storage lipids facilitates homeostatic maintenance of the membrane physical/chemical state that resists negative effects on cell growth and viability in response to HS. We propose a novel stress adaptation mechanism in which heat-induced TG synthesis contributes to membrane rigidization by accommodating unsaturated fatty acids of structural lipids, enabling their replacement by newly synthesized saturated fatty acids.

  12. Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

    Energy Technology Data Exchange (ETDEWEB)

    Kingston, T. [Gas Technology Inst., Des Plaines, IL (United States); Scott, S. [Gas Technology Inst., Des Plaines, IL (United States)

    2013-03-01

    Homebuilders are exploring more cost-effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads and found that the tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system, among other key findings.

  13. Performance Analysis and Application of Three Different Computational Methods for Solar Heating System with Seasonal Water Tank Heat Storage

    Directory of Open Access Journals (Sweden)

    Dongliang Sun

    2013-01-01

    Full Text Available We analyze and compare three different computational methods for a solar heating system with seasonal water tank heat storage (SHS-SWTHS. These methods are accurate numerical method, temperature stratification method, and uniform temperature method. The accurate numerical method can accurately predict the performance of the system, but it takes about 4 to 5 weeks, which is too long and hard for the performance analysis of this system. The temperature stratification method obtains relatively accurate computation results and takes a relatively short computation time, which is about 2 to 3 hours. Therefore, this method is most suitable for the performance analysis of this system. The deviation of the computational results of the uniform temperature method is great, and the time consumed is similar to that of the temperature stratification method. Therefore, this method is not recommended herein. Based on the above analyses, the temperature stratification method is applied to analyze the influence of the embedded depth of water tank, the thickness of thermal insulation material, and the collection area on the performance of this system. The results will provide a design basis for the related demonstration projects.

  14. Conceptual design of a latent heat thermal energy storage subsystem for a saturated steam solar receiver and load

    Science.gov (United States)

    Dilauro, G. F.; Rice, R. E.

    1982-02-01

    The conceptual design of a tube intensive latent heat thermal energy storage (TES) subsystem which utilized a eutectic mixture of sodium hydroxide and sodium nitrate as the phase change material (PCM) was developed. The charging and discharging of the unit is accomplished by the same serpentine tube bundle heat exchanger in which heat transfer is augmented by aluminum channels acting as fins. Every tenth channel is made of steel to provide tube support.

  15. Heat storage in gypsum. Final report to the Energy Agency; Vaermelagring i Gips. Slutrapport foer Energimyndigheten

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Punya (Process Improvements, Plankgatan 26, Norrkoeping (Sweden)); Kindh, Torgny (Environnet AB, Norrkoeping (Sweden)); Lawrence, David; Wahlstroem, Krister (Dept. of Physics, Chemistry and Biology, Linkoeping Univ., Linkoeping (Sweden))

    2007-06-15

    The Swedish Energy Agency's project 'energy storage in gypsum', began in April 2007 and finished a year later. The objective was to demonstrate the potential of using gypsum to store and retrieve low-grade heat at a pilot scale (i.e. using 200 kg of gypsum). Gypsum undergoes a reversible reaction with water in which it stores or releases energy. Preliminary work indicated that when using commercially available gypsum powder, a packed bed would not allow sufficient mass or heat transfer. Preliminary work also revealed that simple fluidization was not possible with the very fine particles: stirred fluidization was the solution used. A pilot-scale unit was constructed (essentially a closed tank about 1 m in diameter and 1 m high). To store energy, hot, dry air is contacted with the gypsum to bring the temperature of the powder to about 110 deg C. Once the powder is 'dried' it is returned to room temperature and isolated from the surroundings - in this state energy is stored indefinitely. To recover the heat, water was atomized, mixed with warm air (to vaporize the water) and reacted with the gypsum. Typically we were able to recover about 6 kWh of energy, which is only about 20% of what is possible. This is partly the result of too little insulation on the reactor and a hesitation to over-hydrate the gypsum (which would result in solid plaster). We anticipate that this will at least double with increased operating experience. Overall gypsum behaves at a pilot scale as was expected; in terms of energy storage for space heating, it shows great promise. Our experiences to date have shown that using gypsum with a larger particle size (to allow simple fluidization) is an important improvement.

  16. NOy production, ozone loss and changes in net radiative heating due to energetic particle precipitation in 2002–2010

    Directory of Open Access Journals (Sweden)

    M. Sinnhuber

    2018-01-01

    Full Text Available We analyze the impact of energetic particle precipitation on the stratospheric nitrogen budget, ozone abundances and net radiative heating using results from three global chemistry-climate models considering solar protons and geomagnetic forcing due to auroral or radiation belt electrons. Two of the models cover the atmosphere up to the lower thermosphere, the source region of auroral NO production. Geomagnetic forcing in these models is included by prescribed ionization rates. One model reaches up to about 80 km, and geomagnetic forcing is included by applying an upper boundary condition of auroral NO mixing ratios parameterized as a function of geomagnetic activity. Despite the differences in the implementation of the particle effect, the resulting modeled NOy in the upper mesosphere agrees well between all three models, demonstrating that geomagnetic forcing is represented in a consistent way either by prescribing ionization rates or by prescribing NOy at the model top.Compared with observations of stratospheric and mesospheric NOy from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS instrument for the years 2002–2010, the model simulations reproduce the spatial pattern and temporal evolution well. However, after strong sudden stratospheric warmings, particle-induced NOy is underestimated by both high-top models, and after the solar proton event in October 2003, NOy is overestimated by all three models. Model results indicate that the large solar proton event in October 2003 contributed about 1–2 Gmol (109 mol NOy per hemisphere to the stratospheric NOy budget, while downwelling of auroral NOx from the upper mesosphere and lower thermosphere contributes up to 4 Gmol NOy. Accumulation over time leads to a constant particle-induced background of about 0.5–1 Gmol per hemisphere during solar minimum, and up to 2 Gmol per hemisphere during solar maximum. Related negative anomalies of ozone are predicted by

  17. Salt gradient solar pond for solar heat collection and long term storage

    Energy Technology Data Exchange (ETDEWEB)

    Unsworth, P.J.; Al-Saleh, N.; Phillips, V.; Butlin, B.

    1985-01-01

    The solar pond project at the University of Sussex aims to study the design, construction, filling, and operation of salt gradient solar ponds, and to develop instrumentation for monitoring behaviour and performance. This paper describes the construction, filling, and operation of an outdoor pilot solar pond, and a simple means of maintaining salt density gradient, as well as work on pond transparency. To obtain high overall operating efficiency we have successfully experimented with extracting heat from both the non-convecting insulation layer and the convecting storage layer of the pond. This permits interception and extraction of heat flow in the non-convecting layer which would otherwise be lost at the surface. We have carried out laboratory and outdoor experiments to test whether this causes unwanted convective mixing in the non-convective zone, and have measured heat transfer coefficients achievable in that layer. Both steady-state and finite difference model calculations are presented to indicate the improvements in operating efficiency and temperature that are achievable with this method of heat extraction. Good applications and limitations are discussed.

  18. Closed loop chemical systems for energy storage and transmission (chemical heat pipe). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vakil, H.B.; Flock, J.W.

    1978-02-01

    The work documents the anlaysis of closed loop chemical systems for energy storage and transmission, commonly referred to as the Chemical Heat Pipe (CHP). Among the various chemical reaction systems and sources investigated, the two best systems were determined to be the high temperature methane/steam reforming reaction (HTCHP) coupled to a Very High Temperature Gas Cooled Reactor (VHTR) and the lower temperature, cyclohexane dehydrogenation reaction (LTCHP) coupled to existing sources such as coal or light water reactors. Solar and other developing technologies can best be coupled to the LTCHP. The preliminary economic and technical analyses show that both systems could transport heat at an incremental cost of approximately $1.50/GJ/160 km (in excess of the primary heat cost of $2.50/GJ), at system efficiencies above 80%. Solar heat can be transported at an incremental cost of $3/GJ/160 km. The use of the mixed feed evaporator concept developed in this work contributes significantly to reducing the transportation cost and increasing the efficiency of the system. The LTCHP shows the most promise of the two systems if the technical feasibility of the cyclic closed loop chemical reaction system can be established. An experimental program for establishing this feasibility is recommended. Since the VHTR is several years away from commercial demonstration and the HTCHP chemical technology is well developed, future HTCHP programs should be aimed at VHTR and interface problems.

  19. Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

    Science.gov (United States)

    Hasan, M. M.; Lin, C. S.; Vandresar, N. T.

    1991-01-01

    Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

  20. Retrospective dosimetry: Dose evaluation using unheated and heated quartz from a radioactive waste storage building

    DEFF Research Database (Denmark)

    Jain, M.; Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    In the assessment of dose received from a nuclear accident, considerable attention has been paid to retrospective dosimetry using heated materials such as household ceramics and bricks. However, unheated materials such as mortar and concrete are more commonly found in industrial sites and particu......In the assessment of dose received from a nuclear accident, considerable attention has been paid to retrospective dosimetry using heated materials such as household ceramics and bricks. However, unheated materials such as mortar and concrete are more commonly found in industrial sites...... and particularly in nuclear installations. These materials contain natural dosemeters Such as quartz. which usually is less sensitive than its heated counterpart. The potential of quartz extracted from mortar in a wall of a low-level radioactive-waste storage facility containing distributed sources of Co-60 and Cs......-137 has been investigated. Dose-depth profiles based on small aliquots and single grains from the quartz extracted from the mortar samples are reported here. These are compared with results from heated quartz and polymineral fine grains extracted from an adjacent brick, and the integrated dose...

  1. Thermal Analysis of a Thermal Energy Storage Unit to Enhance a Workshop Heating System Driven by Industrial Residual Water

    Directory of Open Access Journals (Sweden)

    Wenqiang Sun

    2017-02-01

    Full Text Available Various energy sources can be used for room heating, among which waste heat utilization has significantly improved in recent years. However, the majority of applicable waste heat resources are high-grade or stable thermal energy, while the low-grade or unstable waste heat resources, especially low-temperature industrial residual water (IRW, are insufficiently used. A thermal energy storage (TES unit with paraffin wax as a phase change material (PCM is designed to solve this problem in a pharmaceutical plant. The mathematical models are developed to simulate the heat storage and release processes of the TES unit. The crucial parameters in the recurrence formulae are determined: the phase change temperature range of the paraffin wax used is 47 to 56 °C, and the latent heat is 171.4 kJ/kg. Several thermal behaviors, such as the changes of melting radius, solidification radius, and fluid temperature, are simulated. In addition, the amount of heat transferred, the heat transfer rate, and the heat storage efficiency are discussed. It is presented that the medicine production unit could save 10.25% of energy consumption in the investigated application.

  2. The influence of using heat storage with PCM on inlet and outlet temperatures in substation in DHS

    Science.gov (United States)

    Nogaj, Kinga; Turski, Michał; Sekret, Robert

    2017-11-01

    The main objective of this article is to indicate the direction of development of new generation heating systems that use phase change materials, and the important criteria needed when choosing a phase change material. The work contains a detailed classification of materials using the latent heat of organic and inorganic PCM. This references the technical possibilities of existing heat storage technologies. A specific objective was adopted to determine the effect of using heat storage with PCM on inlet and outlet temperatures in substation in district heating systems. The scope of the study included determining the parameters of the heat distribution network as a function of an outdoor air temperature within the range of -20°C to + 12°C. The object of analysis was chosen to be the heating system parameters: supply 120°C and return 60°C. It is located on the surface of 160km2, and supplies heat to 240,000 residents. The total length of the district heating network is 170 km. Based on the study, it was found that the most advantageous material that accumulates heat depends on the return temperature in the heating network. For the above analyzed case, the return temperature was in the range of 46°C to 57°C. The analysis showed that the most preferred materials using heat of phase change, have possible applications in heating networks and received a return temperature including salt hydrates, such as MgSO4·7H2O and Na2S2O3·5H2. The introduction of stored heat for the district heating system with the phase change material in the form of salt hydrates, allows the return temperature in the district heating to remain at temperatures compatible with the adopted regulatory table for temperatures outside the standard heating season.

  3. Boiling/evaporative heat transfer from spheres in packed-bed thermal energy storage units

    Science.gov (United States)

    Arimilli, R. V.; Moy, C. A.

    1990-05-01

    An experimental study was conducted to study boiling/evaporative heat transfer from heated spheres in vertical packed beds with downward liquid vapor flow of Refrigerant-113. Surface superheats of 1 to 50 C; mass flow rates of 1.7, 2.7, and 5.6 kg/min; sphere diameters of 1.59 and 2.54 cm; quality (i.e., mass fraction of vapor) of the inlet flow of 2 to 100 percent; and two surface roughness conditions were considered. To determine heat transfer coefficients, smooth and roughened aluminum spheres of the same diameter as the other spheres in the bed were instrumented with two thermocouples each for measuring the surface temperatures and a tiny electrical resistance heater for input power. The heat transfer measurements were made under steady-state conditions. Heat transfer coefficients were independently determined for each sphere at three values of surface superheat. The quantitative results are represented as a correlation for the boiling heat transfer coefficients in terms of a homogeneous model. The equation correlates very effectively with the dimensionless temperature difference. The correlation may be used in the development of numerical models to simulate the transient thermal performance of a packed-bed thermal energy storage unit while operating as an evaporator. The boiling of the liquid vapor flow around the spheres in the packed bed was visually observed with a fiber optic boroscope and recorded on a video tape. The visualization results showed qualitatively the presence of our four distinct flow regimes. One of these occurs under subcooled regime. The other three occur under saturated inlet conditions and are referred to as the low-quality, medium-quality, and high-quality regimes. The regimes are discussed in detail.

  4. Domestic olivine versus magnesite as a thermal energy storage material: Performance comparisons for electrically heated room-size units in accordance with ASHRAE standard 94.2

    Science.gov (United States)

    Laster, W. R.; Schoenhals, R. J.; Gay, B. M.; Palmour, H., III

    1982-05-01

    Electrically heated thermal energy storage (TES) heaters employing high heat capacity ceramic refractories for sensible heat storage have been in use in Europe for several years. With these heaters, low cost off peak electrical energy is stored by heating a storage core composed of ceramic material to approximately 800 C. During the peak period, no electrical energy is used as the building heating needs are supplied by extracting the stored heat from the core by forced air circulation. Recently significant interest in the use of off peak TES units in the US has occurred, leading to the search for a domestic supply of high heat capacity ceramic refractory material. North Carolina's extensive but under utilized supply of refractory grade olivine has been proposed as a source of storage material for these units. In this paper, the suitability of North Carolina olivine for heat storage applications is assessed by comparing its thermal performance with that of European materials.

  5. OPTIMIZATION OF INTERNAL HEAT EXCHANGERS FOR HYDROGEN STORAGE TANKS UTILIZING METAL HYDRIDES

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, S.; Tamburello, D.; Hardy, B.; Anton, D.; Gorbounov, M.; Cognale, C.; van Hassel, B.; Mosher, D.

    2011-07-14

    Two detailed, unit-cell models, a transverse fin design and a longitudinal fin design, of a combined hydride bed and heat exchanger are developed in COMSOL{reg_sign} Multiphysics incorporating and accounting for heat transfer and reaction kinetic limitations. MatLab{reg_sign} scripts for autonomous model generation are developed and incorporated into (1) a grid-based and (2) a systematic optimization routine based on the Nelder-Mead downhill simplex method to determine the geometrical parameters that lead to the optimal structure for each fin design that maximizes the hydrogen stored within the hydride. The optimal designs for both the transverse and longitudinal fin designs point toward closely-spaced, small cooling fluid tubes. Under the hydrogen feed conditions studied (50 bar), a 25 times improvement or better in the hydrogen storage kinetics will be required to simultaneously meet the Department of Energy technical targets for gravimetric capacity and fill time. These models and methodology can be rapidly applied to other hydrogen storage materials, such as other metal hydrides or to cryoadsorbents, in future work.

  6. Performance evaluation of solar box cooker assisted with latent heat energy storage system for cooking application

    Science.gov (United States)

    Vigneswaran, V. S.; Kumaresan, G.; Sudhakar, P.; Santosh, R.

    2017-05-01

    Solar cooking is one of the most promising techniques to meet the cooking needs in remote areas where electricity and fuel supplies are meager. Solar box cooker is an efficient device used in solar cooking as it is simple to fabricate, easy to operate and hazard-free. In this context, the performance evaluation of a solar box cooker with varied number of reflectors has been undertaken. It was found that the time consumed for cooking in a box type solar cooker with four reflectors is lesser compared to that of a single reflector and its overall utilization efficiency increases with increase in the cooking mass. Further, a latent heat energy storage system was designed and fabricated to cook the food at off-peak hours of solar radiation. This latent heat energy storage system was combined with the solar box cooker. Oxalic acid dihydrate was used as the phase change material due to its high specific enthalpy and its melting point lying close to the cooking temperature. It was found that the solar box cooker with phase change material could be effectively utilized to cook food during off-peak hours of solar radiation.

  7. Allowable peak heat-up cladding temperature for spent fuel integrity during interim-dry storage

    Directory of Open Access Journals (Sweden)

    Ki-Nam Jang

    2017-12-01

    Full Text Available To investigate allowable peak cladding temperature and hoop stress for maintenance of cladding integrity during interim-dry storage and subsequent transport, zirconium alloy cladding tubes were hydrogen-charged to generate 250 ppm and 500 ppm hydrogen contents, simulating spent nuclear fuel degradation. The hydrogen-charged specimens were heated to four peak temperatures of 250°C, 300°C, 350°C, and 400°C, and then cooled to room temperature at cooling rates of 0.3 °C/min under three tensile hoop stresses of 80 MPa, 100 MPa, and 120 MPa. The cool-down specimens showed that high peak heat-up temperature led to lower hydrogen content and that larger tensile hoop stress generated larger radial hydride fraction and consequently lower plastic elongation. Based on these out-of-pile cladding tube test results only, it may be said that peak cladding temperature should be limited to a level < 250°C, regardless of the cladding hoop stress, to ensure cladding integrity during interim-dry storage and subsequent transport.

  8. Evaluation of a storage cabinet for heat-sensitive endoscopes in a clinical setting.

    Science.gov (United States)

    Grandval, P; Hautefeuille, G; Marchetti, B; Pineau, L; Laugier, R

    2013-05-01

    In most countries, endoscopes must be disinfected or fully reprocessed before the beginning of each session, even if they were cleaned and disinfected after their last use. Several storage cabinets for heat-sensitive endoscopes (SCHE) are commercially available. They are designed to maintain the microbiological quality of reprocessed endoscopes for a predefined period of time validated by the SCHE manufacturer. Use of an SCHE increases the acceptable storage time before it is necessary to re-disinfect the endoscope. To evaluate the efficacy of an SCHE (DSC8000, Soluscope, SAS Marseilles, France) in a clinical setting. The microbiological quality of endoscopes was assessed after 72 h of storage in an SCHE (Group I), and compared with the microbiological quality of endoscopes stored for 72 h in a clean, dry, dedicated cupboard without morning disinfection (Group II) and the microbiological quality of endoscopes stored for 72 h in a clean, dry, dedicated cupboard with morning disinfection (Group III). Forty-one endoscopes in each group were sampled for microbiological quality. Endoscope contamination levels were analysed according to guidelines published by the National Technical Committee on Nosocomial Infection in 2007. Use of an SCHE helps to maintain the microbiological quality of endoscopes, provided that staff members are well trained and all practices are framed by a proven quality assurance process. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  9. Effect of heat storage and fuel price on energy management and economics of micro CCHP cogeneration systems

    Energy Technology Data Exchange (ETDEWEB)

    Askari, I. Baniasad [University of Zabol, Zabol (Iran, Islamic Republic of); Sadegh, M. Oukati [University of Sistan and Baluchestan, Zahedan (Iran, Islamic Republic of); Ameri, M. [Shahid Bahonar University, Kerman (Iran, Islamic Republic of)

    2014-05-15

    In the present work, a typical combined cooling, heating and power (CCHP) system comprised of boiler, flat solar collectors, absorption chiller and heat storage tank was investigated. The described system was considered to supply the given electricity, cooling and heating demand of a residential building; with heating and cooling needs of 100 and 50 kW, respectively. To find the optimum hybrid configurations with high reliability, low costs, low fuel consumption and emissions, a computer program was provided by authors in FORTRAN language. Different fuel prices were considered in the present work. The results indicated that the optimal operation strategy changes with Boiler and NGG fuel prices while it also changes with increasing the number of solar collectors, heat storage capacity and consequently decreasing total annual emission.

  10. Demonstration of Mg2FeH6 as heat storage material at temperatures up to 550 °C

    Science.gov (United States)

    Urbanczyk, R.; Meggouh, M.; Moury, R.; Peinecke, K.; Peil, S.; Felderhoff, M.

    2016-04-01

    The storage of heat at high temperatures, which can be used to generate electricity after sunset in concentrating solar power plants, is one of the most challenging technologies. The use of metal hydride could be one possibility to solve the problem. During the endothermic heat storage process, the metal hydride is decomposed releasing hydrogen, which then can be stored. During the exothermic reaction of the metal with the hydrogen gas, the stored heat is then released. Previous research had shown that Mg and Fe powders can be used at temperatures up to 550 °C for heat storage and shows excellent cycle stability over hundreds of cycles without any degradation. Here, we describe the results of testing of a tube storage tank that contained 211 g of Mg and Fe powders in 2:1 ratio. Twenty-three dehydrogenations (storage) and 23 hydrogenations (heat release) in the temperature range between of 395 and 515 °C and pressure range between 1.5 and 8.6 MPa were done. During the dehydrogenation, 0.41-0.42 kWhth kg-1 of heat based on material 2 Mg/Fe can be stored in the tank. After testing, mainly Mg2FeH6 was observed and small amounts of MgH2 and Fe metal can be detected in the hydride samples. This means that the heat storage capacity of the system could be further increased if only Mg2FeH6 is produced during subsequent cycles.

  11. GEOMETRY, HEAT REMOVAL AND KINETICS SCOPING MODELS FOR HYDROGEN STORAGE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, B

    2007-11-16

    It is recognized that detailed models of proposed hydrogen storage systems are essential to gain insight into the complex processes occurring during the charging and discharging processes. Such insight is an invaluable asset for both assessing the viability of a particular system and/or for improving its design. The detailed models, however, require time to develop and run. Clearly, it is much more efficient to begin a modeling effort with a good system design and to progress from that point. To facilitate this approach, it is useful to have simplified models that can quickly estimate optimal loading and discharge kinetics, effective hydrogen capacities, system dimensions and heat removal requirements. Parameters obtained from these models can then be input to the detailed models to obtain an accurate assessment of system performance that includes more complete integration of the physical processes. This report describes three scoping models that assess preliminary system design prior to invoking a more detailed finite element analysis. The three models address the kinetics, the scaling and heat removal parameters of the system, respectively. The kinetics model is used to evaluate the effect of temperature and hydrogen pressure on the loading and discharge kinetics. As part of the kinetics calculations, the model also determines the mass of stored hydrogen per mass of hydride (in a particular reference form). As such, the model can determine the optimal loading and discharge rates for a particular hydride and the maximum achievable loading (over an infinite period of time). The kinetics model developed with the Mathcad{reg_sign} solver, runs in a mater of seconds and can quickly be used to identify the optimal temperature and pressure for either the loading or discharge processes. The geometry scoping model is used to calculate the size of the system, the optimal placement of heat transfer elements, and the gravimetric and volumetric capacities for a particular

  12. Passive Residential Houses with the Accumulation Properties of Ground as a Heat Storage Medium

    Science.gov (United States)

    Ochab, Piotr; Kokoszka, Wanda; Kogut, Janusz; Skrzypczak, Izabela; Szyszka, Jerzy; Starakiewicz, Aleksander

    2017-12-01

    Solar radiation is the primary source of life energy on Earth. The irradiance of the upper atmosphere is about 1360 W/m2, and it is estimated that about 1000 W/m2 reaches the ground. Long-term storage of heat energy is related to the use of a suitable thermal energy carrier. It may be either artificial or natural water tank, or artificial gravel-water tank, or aquifer or soil. It is justified to store the generated energy in large heating systems due to the nature of solar thermal energy. Typically, in such a solution storage space is a large solar collector farm. The reason for this is the proportionally small unit profits, which only in the case of large number of units provides sufficient energy that can be accumulated. It should be noted that Poland, a country located in a temperate and less harsh climate such as Scandinavia and Canada, has a relatively high potential for solar revenue. In the last decade, it has caused mainly small and individual heating installations. However, much of the municipal and industrial economy continues to rely on energy from non-renewable resources. This is due not only to the lack of a high-efficiency alternative to non-renewable energy resources, but also to the thermal state of buildings throughout the country, where old buildings require thermomodernization. This has the effect of both polluting the environment and the occurrence of smog, as well as pollutants in water and soil. This directly affects the occurrence of civilization diseases and other societal health problems. Therefore, the surplus of thermal clean energy that occurs during the spring and summer period should not only be used on a regular basis, but also stored for later winter use. The paper presents the concept of housing estate, which consists of 32 twin housing units. The solid character of buildings consistently refers to passive construction, and the materials meet the requirements for the passive buildings.

  13. Influence of prolonged storage process, pasteurization, and heat treatment on biologically-active human milk proteins.

    Science.gov (United States)

    Chang, Jih-Chin; Chen, Chao-Huei; Fang, Li-Jung; Tsai, Chi-Ren; Chang, Yu-Chuan; Wang, Teh-Ming

    2013-12-01

    The bioactive proteins in human milk may be influenced by prolonged storage process, pasteurization, and heat treatment. This study was conducted to evaluate the effects of these procedures. Three forms of human milk - freshly expressed, frozen at -20°C for a prolonged duration, and pasteurized milk - were collected from 14 healthy lactating mothers and a milk bank. The concentrations of major bioactive proteins (secretory immunoglobulin A, lactoferrin, lysozyme, and leptin) were quantified using enzyme-linked immunosorbent assay kits. Changes in these proteins by heat treatment at 40°C or 60°C for 30 minutes were further evaluated. The mean concentrations of lactoferrin and secretory immunoglobulin A were significantly reduced by 66% and 25.9%, respectively, in pasteurized milk compared with those in freshly-expressed milk. Heat treatment at 40°C or 60°C did not cause significant changes in lactoferrin and secretory immunoglobulin A, but there was an apparent increase in lysozyme (p = 0.016). There were no significant differences in leptin level among these three forms of milk prior to (p = 0.153) or after heat treatment (p = 0.053). Various freezing/heating/pasteurization processes applied to human milk prior to delivery to neonates could affect the concentration of immunomodulatory proteins, especially lactoferrin, secretory immunoglobulin A, and lysozyme. Leptin was unaffected by the various handling processes tested. Fresh milk was found to be the best food for neonates. Further studies are warranted to evaluate the functional activity of these proteins and their effects on infants' immunological status. Copyright © 2013. Published by Elsevier B.V.

  14. EFFECTS OF HEAT TREATMENT AND CALCIUM ON POSTHARVEST STORAGE OF ATEMOYA FRUITS*

    Directory of Open Access Journals (Sweden)

    LIZ MARIA ABI RACHED TORRES

    2010-03-01

    Full Text Available

    The aim of the present study was to investigate the effect of postharvest warm dipping with calcium chloride (CaCl2 on atemoya fruit (Annona cherimola Mill x Annona squamosa L. storage. Fruits were immersed in 6% CaCl2 solution at 20 and 40°C for 20 min followed by storage at room temperature. The effectiveness of the treatment was assessed in terms of its impact on peel and fl esh appearance, weight loss, total soluble solids (TSS, total titratable acidity (TTA, pH, ascorbic acid content, total phenolics, and enzyme activities of polyphenoloxidase (PPO and peroxidase (POD. Treatment at 40°C preserved eatable conditions up to 6 days, although calcium affected the appearance of the peel as soon as 4 days. Flesh browning was detected only on the 8th day in untreated fruits, after an increase in PPO and POD activities and total phenolics, and a decrease in ascorbic acid content. The weight loss was continuous throughout the storage period, with no signifi cant difference between treatments. TTA and TSS contents increased and pH decreased during the experiment. Results suggest that CaCl2 dipping had a positive effect on fl esh browning, which was reduced, while heat treatment showed a synergic effect, which could be related broadly with a fall in PPO activity. The variations in ascorbic acid content during storage suggest that the warm dipping combined with CaCl2, contributed to the antioxidant capacity of the fruit.

  15. Development of PFAS-heat storage type air conditioning system with individual heat pump. Chikunetsushiki kobetsu hito ponpu kucho system 'PFAS' no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, S. (Tokyo Electric Power Co., Inc. (Japan)); Seki, Y. (Takasago Thermal Engineering Co. Ltd., Tokyo (Japan)); Igarashi, M. (Nippon P-MAC Co. Ltd., Tokyo (Japan))

    1993-12-05

    With various uses of building, a good air conditioning system with individual control is needed. Meanwhile, the maximum electric power during summer days is increasing year by year, equalization of electricity load consumed by air conditioning system becomes an important subject in the aspect of stable supply of energy. For meeting these requirements, authors developed a system of the PMAC fancoil air conditioning and heat storage system (PFAS) which provides with a distributed individual type hydrothermal source air conditioner and a heat storage system. This paper introduced a summary of the PFAS system and some operating examples. This system was constructed by the air conditioning unit of combining a hydrothermal source unitary heat pump with a fancoil, a machine of a heat source such as an air cooling heat pump, a heat storage tank and a control system, and it realized equalization of electricity load consumed and saving the running cost of the air conditioning system owing to the night electric use. 8 refs.

  16. Designing and testing an air-PCM heat exchanger for building ventilation application coupled to energy storage

    OpenAIRE

    Dechesne, Bertrand; Gendebien, Samuel; Martens, Jonathan; Gilbert, Jacques; Lemort, Vincent

    2014-01-01

    This paper studies a PCM heat exchanger coupled to a building ventilation system. This PCM module can either store heat during the day (e.g. by cooling solar PV panels) and restore it to the building during the night for space heating purposes or store coolness during the night and give it back during the day and thus act as a free cooling system. This project aims to develop a performing air-PCM heat exchanger providing latent energy storage of 0.5 kWh, this energy is deliver...

  17. Underground seasonal storage of industrial waste heat; Saisonale Speicherung industrieller Abwaerme im Untergrund

    Energy Technology Data Exchange (ETDEWEB)

    Reuss, M.; Mueller, J. [Bayerische Landesanstalt fuer Landtechnik, TU Muenchen-Weihenstephan, Freising (Germany)

    1998-12-31

    The thermal efficiency of subject systems, especially at higher temperatures is influenced by heat and humidity transport underground. Thermal conductivity and specific thermal capacity depend on the humidity content of the soil. A simulation model was developed that describes the coupled heat and humidity transport in the temperature range up to 90 C. This model will be validated in laboratory and field tests and then be used for designing and analysing underground stores. Pilot plants for the storage of industrial waste heat were designed and planned on the basis of this simulation. In both cases these are cogeneration plants whose waste heat was to be used for space heating and as process energy. Both plants have a very high demand of electric energy which is mostly supplied by the cogeneration plant. The waste heat is put into the store during the summer. In the winter heat is supplied by both the store and the cogeneration plant. In both cases the store has a volume of approx. 15,000 cubic metres with 140 and 210 pits located in a depth of 30 and 40 metres. The plants are used to carry out extensive measurements for the validation of simulation models. (orig.) [Deutsch] Die thermische Leistungsfaehigkeit solcher Systeme wird insbesondere im hoeheren Temperaturbereich durch den Waerme- und Feuchtetransport im Untergrund beeinflusst. Sowohl die Waermeleitfaehigkeit als auch die spezifische Waermekapazitaet sind vom Feuchtegehalt des Bodens abhaengig. Es wurde ein Simulationsmodell entwickelt, das den gekoppelten Waerme- und Feuchtetransport im Temperaturbereich bis 90 C beschreibt. Dieses Modell wird an Labor- und Feldexperimenten validiert und dient dann zur Auslegung und Analyse von Erdwaermesonden-Speichern. Basierend auf diesen theoretischen Grundlagenarbeiten wurden Pilotanlagen zur saisonalen Speicherung industrieller Abwaerme ausgelegt und geplant. In beiden Faellen handelt es sich um Kraft/Waermekopplungsanlagen, deren Abwaerme zur Gebaeudeheizung und

  18. Changes in carbon storage and net carbon exchange one year after an initial shelterwood harvest at Howland Forest, ME

    Science.gov (United States)

    Neal A. Scott; Charles A. Rodrigues; Holly Hughes; John T. Lee; Eric A. Davidson; D Bryan Dail; Phil Malerba; David Y. Hollinger

    2004-01-01

    Although many forests are actively sequestering carbon, little research has examined the direct effects of forest management practices on carbon sequestration. At the Howland Forest in Maine, USA, we are using eddy covariance and biometric techniques to evaluate changes in carbon storage following a shelterwood cut that removed just under 30% of aboveground biomass....

  19. The Heat Transfer of Microencapsulated Phase Change Material Slurry and Its Thermal Energy Storage Performance of Combined Heat and Power Generating Units

    Directory of Open Access Journals (Sweden)

    Yonghong Guo

    2017-10-01

    Full Text Available The application of thermal energy storage (TES is an effective way of improving the power load regulation capability of combined heat and power (CHP generating units. In this paper, a theoretical investigation on the thermal energy storage system of a CHP unit that employs the microencapsulated phase change material slurry (MPCMS as the working fluid is carried out. The results indicate that the microcapsule particle internal melting rate is progressively small; 90% latent heat can be absorbed in 63% total melting time. The melting time of particles in micron is very short, and the diameter is an important factor for microcapsule melting. For the MPCMS flow in a circular tube, the temperature distribution between laminar flows and turbulent flows is different. In a turbulent flow, there is an approximate isothermal section along the tube, which cannot be found in a laminar flow. Additionally, a thermal storage system with MPCMS as heat transfer fluid for a CHP unit is proposed. A case study for a 300 MW CHP unit found that the use of an MPSMS thermal energy storage system increases the power peak shaving capacity by 81.4%. This indicates that the thermal storage system increases the peak shaving capacity of cogeneration units.

  20. Latent heat storage in a solar thermal cooling system. Final report; Latentwaermespeicherung in einer solarthermisch angetriebenen Absorptionsklimakaelteanlage. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Gramlich, K.; Safarik, M.; Schammler, G.

    2001-07-31

    There are not latent heat storage systems in the temperature range above 90 C available at present. For solar thermal cooling the heat has to be provided at this level. The purpose of this study was to quantify the storage capacity and the performance of charging and discharging of a new developed 1 m{sup 3}-latent heat storage system and the constancy of the heat of fusion of the used paraffin. The latent heat storage system was installed and tested as part of a solar thermal cooling system. The constancy of the melting point was separately measured. After melting and solidifying 500 times the melting point of the tested paraffin was still unchanged. Once melted the paraffin in the storage remains more the 36 hours in this state. Therefore the fluctuations in solar radiation and cooling demand over the day can be compensated. Because of the small thermal conductivity of the paraffin the velocity of heat transfer is small, too. The performance is increased by adding metal carrier material to the storage. The latent heat storage system is capable to work within a solar thermal cooling system because of its composition, the used heat storage material and the integration into the whole system. (orig.) [German] Latent-Waermespeicher im Temperaturbereich ueber 90 C sind z.Z. nicht verfuegbar. Fuer die solarthermische Klimakaelteerzeugung muss die Antriebswaerme auf diesem Temperaturniveau bereitgestellt werden. Ziel der Untersuchungen waren Messungen zur Speicherkapazitaet, zur Lade- und Entladeleistung und zur Konstanz der Schmelzenthalpie von Paraffin in einem neu konstruierten 1000 l - Speicher. Der Paraffin-Latentwaermespeicher wurde in einer Solarthermieanlage zur Klimakaelteerzeugung integriert und die Speicherfunktionen im Anlagenbetrieb untersucht. Die Stabilitaet der Schmelztemperatur in Abhaengigkeit von den Phasenwechseln wurde separat gemessen. Die Schmelztemperatur bleibt nach ueber 500 Phasenwechseln konstant. Das Paraffin konnte ueber 36 Stunden im

  1. Dynamic thermal behavior of building using phase change materials for latent heat storage

    Directory of Open Access Journals (Sweden)

    Selka Ghouti

    2015-01-01

    Full Text Available This study presents a two-dimensional model with a real size home composed of two-storey (ground and first floor spaces separated by a slab, enveloped by a wall with rectangular section containing phase change material (PCM in order to minimize energy consumption in the buildings. The main objective of the PCM-wall system is to decrease the temperature change from outdoor space before it reaches the indoor space during the daytime. The numerical approach uses effective heat capacity Ceff model with realistic outdoor climatic conditions of Tlemcen city, Algeria. The numerical results showed that by using PCM in wall as energy storage components may reduce the room temperature by about 6 to 7°C of temperature depending on the floor level (first floor spaces or ground floor spaces.

  2. Numerical analysis of melting of nano-enhanced phase change material in latent heat thermal energy storage system

    Directory of Open Access Journals (Sweden)

    Kashani Sina

    2014-01-01

    Full Text Available The heat transfer enhancement in the latent heat thermal energy storage system through dispersion of nanoparticle is reported. The resulting nanoparticle-enhanced phase change materials exhibit enhanced thermal conductivity in comparison to the base material. Calculation is performed for nanoparticle volume fraction from 0 to 0.08. In this study rectangular and cylindrical containers are modeled numerically and the effect of containers dimensions and nano particle volume fraction are studied. It has been found that the rectangular container requires half of the melting time as for the cylindrical container of the same volume and the same heat transfer area and also, higher nano particle volume fraction result in a larger solid fraction. The increase of the heat release rate of the nanoparticle-enhanced phase change materials shows its great potential for diverse thermal energy storage application.

  3. Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation.

    Science.gov (United States)

    Bain, A R; Lesperance, N C; Jay, O

    2012-10-01

    To assess whether, under conditions permitting full evaporation, body heat storage during physical activity measured by partitional calorimetry would be lower with warm relative to cold fluid ingestion because of a disproportionate increase in evaporative heat loss potential relative to internal heat transfer with the ingested fluid. Nine males cycled at 50% VO(2max) for 75 min at 23.6 ± 0.6 °C and 23 ± 11% RH while consuming water of either 1.5 °C, 10 °C, 37 °C or 50 °C in four 3.2 mL kg(-1) boluses. The water was administered 5 min before and 15, 30 and 45 min following the onset of exercise. No differences in metabolic heat production, sensible or respiratory heat losses (all P > 0.05) were observed between fluid temperatures. However, while the increased internal heat loss with cold fluid ingestion was paralleled by similar reductions in evaporative heat loss potential at the skin (E(sk) ) with 10 °C (P = 0.08) and 1.5 °C (P = 0.55) fluid, the increased heat load with warm (50 °C) fluid ingestion was accompanied by a significantly greater E(sk) (P = 0.04). The resultant calorimetric heat storage was lower with 50 °C water ingestion in comparison to 1.5 °C, 10 °C and 37 °C (all P heat storage derived conventionally using thermometry yielded higher values following 50 °C fluid ingestion compared to 1.5 °C (P = 0.025). Under conditions permitting full sweat evaporation, body heat storage is lower with warm water ingestion, likely because of disproportionate modulations in sweat output arising from warm-sensitive thermosensors in the esophagus/stomach. Local temperature changes of the rectum following fluid ingestion exacerbate the previously identified error of thermometric heat storage estimations. © 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.

  4. Thermal Energy Storage for Building Load Management: Application to Electrically Heated Floor

    Directory of Open Access Journals (Sweden)

    Hélène Thieblemont

    2016-07-01

    Full Text Available In cold climates, electrical power demand for space conditioning becomes a critical issue for utility companies during certain periods of the day. Shifting a portion or all of it to off-peak periods can help reduce peak demand and reduce stress on the electrical grid. Sensible thermal energy storage (TES systems, and particularly electrically heated floors (EHF, can store thermal energy in buildings during the off-peak periods and release it during the peak periods while maintaining occupants’ thermal comfort. However, choosing the type of storage system and/or its configuration may be difficult. In this paper, the performance of an EHF for load management is studied. First, a methodology is developed to integrate EHF in TRNSYS program in order to investigate the impact of floor assembly on the EHF performance. Then, the thermal comfort (TC of the night-running EHF is studied. Finally, indicators are defined, allowing the comparison of different EHF. Results show that an EHF is able to shift 84% of building loads to the night while maintaining acceptable TC in cold climate. Moreover, this system is able to provide savings for the customer and supplier if there is a significant difference between off-peak and peak period electricity prices.

  5. Geochemical implications of production and storage control by coupling a direct-use geothermal system with heat networks

    OpenAIRE

    Daniilidis, Alexandros; Scholten, Tjardo; Hooghiem, Joram; De Persis, Claudio; Herber, Rien

    2017-01-01

    This paper outlines a method in which the heat production of a geothermal system is controlled in relation to the demand from a district-heating network. A model predictive control strategy is designed, which uses volume measurements in the storage tank, and predictions of the demand, to regulate the production of the geothermal system in real time. The implications of such time-varying production for the reservoir are investigated using a 2D reactive transport reservoir model. As a case stud...

  6. Sustainable energy supply for mushroom cultivation. Application of underground energy storage. Application of a heat pump for heat production. Feasibility study; Duurzame energievoorziening paddestoelen kwekerij. toepassing van energieopslag in de bodem. Toepassing van warmtepomp voor warmteopwekking. Een haalbaarheidsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Koel, J.J. [EBS-Adviseurs, Veenendaal (Netherlands)

    2001-02-26

    The results of a feasibility study on the use of heat and cold storage and the use of an electric heat pump for the energy supply of a mushroom cultivation business (Verbruggen paddestoelen in Erp, Netherlands) are presented.

  7. Central receiver solar thermal power system, Phase 1. CDRL Item 2. Pilot plant preliminary design report. Volume V. Thermal storage subsystem. [Sensible heat storage using Caloria HT43 and mixture of gravel and sand

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The proposed 100-MWe Commercial Plant Thermal Storage System (TSS) employs sensible heat storage using dual liquid and solid media for the heat storage in each of four tanks, with the thermocline principle applied to provide high-temperature, extractable energy independent of the total energy stored. The 10-MW Pilot Plant employs a similar system except uses only a single tank. The high-temperature organic fluid Caloria HT43 and a rock mixture of river gravel and No. 6 silica sand were selected for heat storage in both systems. The system design, installation, performance testing, safety characteristics, and specifications are described in detail. (WHK)

  8. The capric and lauric acid mixture with chemical additives as latent heat storage materials for cooling application

    Energy Technology Data Exchange (ETDEWEB)

    Roxas-Dimaano, M.N. [University of Santo Tomas, Manila (Philippines). Research Center for the Natural Sciences; Watanabe, T. [Tokyo Institute of Technology (Japan). Research Laboratory for Nuclear Reactors

    2002-09-01

    The mixture of capric acid and lauric acid (C-L acid), with the respective mole composition of 65% and 35%, is a potential phase change material (PCM). Its melting point of 18.0{sup o}C, however, is considered high for cooling application of thermal energy storage. The thermophysical and heat transfer characteristics of the C-L acid with some organic additives are investigated. Compatibility of C-L acid combinations with additives in different proportions and their melting characteristics are analyzed using the differential scanning calorimeter (DSC). Among the chemical additives, methyl salicylate, eugenol, and cineole presented the relevant melting characteristics. The individual heat transfer behavior and thermal storage performance of 0.1 mole fraction of these additives in the C-L acid mixture are evaluated. The radial and axial temperature distribution during charging and discharging at different concentrations of selected PCM combinations are experimentally determined employing a vertical cylindrical shell and tube heat exchanger. The methyl salicylate in the C-L acid provided the most effective additive in the C-L acid. It demonstrated the least melting band width aimed at lowering the melting point of the C-L acid with the highest heat of fusion value with relatively comparable rate of heat transfer. Furthermore, the thermal performance based on the total amount of transferred energy and their rates, established the PCM's latent heat storage capability. (author)

  9. Development of a Hydrogen and Heat Storage System for Satellite Applications

    Science.gov (United States)

    Reissner, Alexander; Pawelke, Roland; Hummel, Stefan; Gerger, Joachim; Lutz, Matthias; Farnes, Jarle; Vik, Arild; Wernhus, Ivar; Svendsen, Tjalve; Schautz, Max; Geneste, Xavier

    2014-08-01

    Next generation telecommunication satellites will demand increasingly more power in the range of 30 kW or more within the next 10 years. Battery technology that can sustain 30 kW for an eclipse length of up to 72 minutes will represent a major impact on the total mass of the satellite, even with new Li-ion battery technologies. Regenerative fuel cell systems (RFCS) were identified years ago as a possible alternative to rechargeable batteries. They consist of a dedicated fuel cell unit for electricity generation and a dedicated electrolyser which regenerates the fuel cell reactants hydrogen and oxygen from the fuel cell reaction product water. All units are integrated in a closed loop system. Nevertheless, one major drawback has been identified by several independent system studies [4,5], namely the need to dissipate large amounts of heat from the fuel cell during Eclipse. This in turn requires massive thermal hardware (mainly large radiators) that can contribute up to 50% of the system mass. FOTEC has suggested the use of metal hydrides as combined hydrogen and heat storage system to overcome this issue and is currently manufacturing a technology demonstrator within an ongoing ESA project. The status of these developments is outlined in this paper.

  10. Proceedings of solar energy storage options. Volume I. An intensive workshop on thermal energy storage for solar heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    Separate abstracts were prepared for the 28 papers presented. Panel chairmen's summaries are included; the complete panel reports will be published in Volume II of the Solar Energy Storage Options Workshop proceedings. (WHK)

  11. Applications of thermal energy storage to process heat storage and recovery in the paper and pulp industry

    Science.gov (United States)

    Carr, J. H.; Hurley, P. J.; Martin, P. J.

    1978-01-01

    Applications of Thermal Energy Storage (TES) in a paper and pulp mill power house were studied as one approach to the transfer of steam production from fossil fuel boilers to waste fuel of (hog fuel) boilers. Data from specific mills were analyzed, and various TES concepts evaluated for application in the process steam supply system. Constant pressure and variable pressure steam accumulators were found to be the most attractive storage concepts for this application.

  12. Safety issues related to the intermediate heat storage for the EU DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Carpignano, Andrea [NEMO group, Dipartimento Energia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Pinna, Tonio [ENEA, 00044 Frascati (Italy); Savoldi, Laura; Sobrero, Giulia; Uggenti, Anna Chiara [NEMO group, Dipartimento Energia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Zanino, Roberto, E-mail: roberto.zanino@polito.it [NEMO group, Dipartimento Energia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2016-11-01

    Highlights: • IHS affects only the PHTS and the BoP (Balance of Plant). • PIEs list does not change but IHS influences PIEs evolution. • Additional issues to be addressed in PIEs study due to the implementation of HIS. • No safety/operational major obstacles were found for IHS concept. - Abstract: The functional deviations able to compromise system safety in the EU DEMO Primary Heat Transfer System (PHTS) with intermediate heat storage (IHS) based on molten salts are identified and compared to the deviations identified with PHTS without IHS. The resulting safety issues for the Balance of Plant (BoP) have been taken into account. Functional Failure Mode and Effects Analysis (FFMEA) is used to highlight the Postulated Initiating Events (PIE) of incident/accident sequences and to provide some safety insights during the preliminary design. The architecture of the system with IHS does not introduce new PIE with respect to the case without IHS, but it modifies some of them. In particular the two Postulated Initiating Events that are affected by the presence of IHS are the LOCA in the tubes of the HX between primary and intermediate circuit and the loss of heat sink for the first wall or the breeding zone. In fact the IHS introduces some advantages concerning the stability of the secondary circuit, but some weaknesses are associated to the physical-chemical nature of molten salts, especially oxidizing power, corrosive nature and risk of solidification. These issues can be managed in the design by the introduction of new safety functions.

  13. Power-to-heat in adiabatic compressed air energy storage power plants for cost reduction and increased flexibility

    Science.gov (United States)

    Dreißigacker, Volker

    2017-10-01

    The development of new technologies for large-scale electricity storage is a key element in future flexible electricity transmission systems. Electricity storage in adiabatic compressed air energy storage (A-CAES) power plants offers the prospect of making a substantial contribution to reach this goal. This concept allows efficient, local zero-emission electricity storage on the basis of compressed air in underground caverns. The compression and expansion of air in turbomachinery help to balance power generation peaks that are not demand-driven on the one hand and consumption-induced load peaks on the other. For further improvements in cost efficiencies and flexibility, system modifications are necessary. Therefore, a novel concept regarding the integration of an electrical heating component is investigated. This modification allows increased power plant flexibilities and decreasing component sizes due to the generated high temperature heat with simultaneously decreasing total round trip efficiencies. For an exemplarily A-CAES case simulation studies regarding the electrical heating power and thermal energy storage sizes were conducted to identify the potentials in cost reduction of the central power plant components and the loss in round trip efficiency.

  14. Changes in proteins, physical stability and structure in directly heated UHT milk during storage at different temperatures

    NARCIS (Netherlands)

    Malmgren, Bozena; Ardö, Ylva; Langton, Maud; Altskär, Annika; Bremer, Maria G.E.G.; Dejmek, Petr; Paulsson, Marie

    2017-01-01

    Changes occurring in directly heated UHT milk were studied during storage at 5, 22, 30 and 40 °C. Industrially produced UHT milk samples were analysed for changes in enzymatic activity, protein modification, destabilisation of casein micelles and relocation of milk proteins in relation to

  15. Improved performance of heat pumps helps to use full potential of subsurface space for Aquifer Thermal Energy Storage

    NARCIS (Netherlands)

    Bloemendal, J.M.; Jaxa-Rozen, M.; Rostampour Samarin, V.

    2017-01-01

    The application of seasonal Aquifer Thermal Energy Storage (ATES) contributes to meet goals for energy savings and greenhouse gas (GHG) emission reductions. Heat pumps have a crucial position in ATES systems because they dictate the operation scheme of the ATES wells and therefore play an important

  16. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating...

  17. Heat Production and Storage Are Positively Correlated with Measures of Body Size/Composition and Heart Rate Drift during Vigorous Running

    Science.gov (United States)

    Buresh, Robert; Berg, Kris; Noble, John

    2005-01-01

    The purposes of this study were to determine the relationships between: (a) measures of body size/composition and heat production/storage, and (b) heat production/storage and heart rate (HR) drift during running at 95 % of the velocity that elicited lactate threshold, which was determined for 20 healthy recreational male runners. Subsequently,…

  18. Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

    Energy Technology Data Exchange (ETDEWEB)

    Kingston, T.; Scott, S.

    2013-03-01

    Homebuilders are exploring more cost effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads with the following key findings: 1) The tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system. 2) The tankless combo system consistently achieved better daily efficiencies (i.e. 84%-93%) than the storage combo system (i.e. 81%- 91%) when the air handler was sized adequately and adjusted properly to achieve significant condensing operation. When condensing operation was not achieved, both systems performed with lower (i.e. 75%-88%), but similar efficiencies. 3) Air handlers currently packaged with combo systems are not designed to optimize condensing operation. More research is needed to develop air handlers specifically designed for condensing water heaters. 4) System efficiencies greater than 90% were achieved only on days where continual and steady space heating loads were required with significant condensing operation. For days where heating was more intermittent, the system efficiencies fell below 90%.

  19. Heat recovery from a thermal energy storage based on the Ca(OH){sub 2}/CaO cycle

    Energy Technology Data Exchange (ETDEWEB)

    Azpiazu, M.N. [E.T.S. Ingenieros, Bilbao (Spain). Dpto. de Ingenieria Quimica y del Medio Ambiente; Morquillas, J.M. [E.T.S. Ingenieros, Bilbao (Spain). Dpto. de Maquinas y Motores Termicos; Vazquez, A. [E.S. da Marina Civil, La Coruna (Spain). Dpto. de Energia y Propulsion Maritima

    2003-04-01

    Thermal energy storage is very important in many applications related to the use of waste heat from industrial processes, renewable energies or from other sources. Thermochemical storage is very interesting for long-term storage as it can be carried out at room temperature with no energy losses. Dehydration/hydration cycle of Ca(OH){sub 2}/CaO has been applied for thermal energy storage in two types of reactors. One of them was a prototype designed by the authors, and in the other type conventional laboratory glassware was used. Parameters such as specific heats, reaction rate and enthalpy, mass losses and heat release were monitored during cycles. Although in the hydration step water is normally added in vapour phase, liquid water, at 0{sup o}C has been used in these experiences. Results indicated that the energy storage system performance showed no significant differences, when we compared several hydration/dehydration cycles. The selected chemical reaction did not exhibit a complete reversibility because complete Ca(OH){sub 2} dehydration, was not achieved. However the system could be used satisfactorily along 20 cycles at least. Heat recovery experiments showed general system behaviour during the hydration step in both types of reactors. The designed prototype was more efficient in this step. Main conclusions suggested carrying out one complete cycle at a higher dehydration temperature to recover total system reversibility. A modification of the prototype design trying to enhance heat transfer from the Ca(OH){sub 2} bed could also be proposed. (author)

  20. Heat Storage Performance of the Prefabricated Hollow Core Concrete Deck Element with Integrated Microencapsulated Phase Change Material

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    The paper presents the numerically calculated dynamic heat storage capacity of the prefabricated hollow core concrete deck element with and without microencapsulated phase change material (PCM). The reference deck is the ordinary deck made of standard concrete material and that is broadly used...... or the building with such a deck is that the thermal properties of such a new material are not yet well defined. The results presented in the paper include models in which PCM concrete material properties such as thermal conductivity and specific heat capacity were theoretically calculated using weight average...... of thermal properties of standard concrete material and pure PCM. Consequently, the numerical models of the decks were updated with the experimentally determined thermal properties of PCM concrete after these two materials have been combined into one material. Finally, the heat storage of the decks...

  1. Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

    Science.gov (United States)

    Anderson, Frank; Bergamaschi, Brian; Windham-Myers, Lisamarie; Woo, Isa; De La Cruz, Susan; Drexler, Judith; Byrd, Kristin; Thorne, Karen M.

    2016-06-24

    Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils.In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook (Oncorhynchus tshawytscha) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO2) uptake through plant photosynthesis, the loss of CO2 through plant and soil respiration, emissions of methane (CH4), and the lateral movement or leaching loss of C in tidal waters.

  2. Large-volume heat storage tank made of GFK; Grosswaermespeichertank aus GFK

    Energy Technology Data Exchange (ETDEWEB)

    Buehl, J.; Schultheis, P. [Technische Univ. Ilmenau (Germany). Fachgebiet Technische Thermodynamik

    1998-12-31

    The Technical University of Ilmenau, the company Verbundwerkstoff- und Kunststoffanwendungstechnik Schoenbrunn, the Institute for Aerospace and Light-weight construction of Dresden University with its approved testing facilities for plastics and the Institute for Construction Engineering in Berlin and several other institutions co-operated since 1996 in developing a concept for a series of long-term heat storage tanks up to 6,000 cubic metres storage volume made of plastic (GFK components) with a combined thermal insulation. A model tank (sandwich body with proportional thermal insulation layer and selected mixed laminates) with a volume of 1.5 cubic metres was built and installed in November 1996. The tank has been continuously operated at various test levels. The experiment proves the longevity of the materials used. (orig.) [Deutsch] In Zusammenarbeit der TU Ilmenau mit der Fa. Verbundwerkstoff - und Kunststoffanwendungstechnik Schoenbrunn und dem Institut fuer Luftfahrttechnik und Leichtbau Dresden, seiner akkredierten Pruefstelle fuer Kunststoffe, in Abstimmung mit dem Institut fuer Bautechnik Berlin und weiteren Einrichtungen und Partnern wird seit 1996 an einem Konzept fuer eine Typenreihe Langzeitwaermespeicher bis vorerst 6.000 m{sup 3} Speichervolumen aus Kunststoff (GFK-Komponenten) und kombinierter integrierter thermischer Isolation gearbeitet. Im Vorfeld dieser Entwicklung wurde auf der Basis vorausgewaehlter Materialien und Kompositionen ein Musterspeicher (ein Sandwich - Modellkoerper mit proportionaler Waermedaemmschicht sowie ausgewaehlten Mischlaminaten) mit einem Speichervolumen von 1,5 m{sup 3} realisiert. Dieser Musterspeicher wurde im November 1996 installiert und wird seither kontinuierlich in den entsprechenden Erprobungsstufen betrieben. Der Nachweis der Langlebigkeit der eingesetzten Materialien wurde experimentell erbracht. (orig.)

  3. Solar Thermoelectricity via Advanced Latent Heat Storage: A Cost-Effective Small-Scale CSP Application

    Energy Technology Data Exchange (ETDEWEB)

    Glatzmaier, Greg C.; Rea, J.; Olsen, Michele L.; Oshman, C.; Hardin, C.; Alleman, Jeff; Sharp, J.; Weigand, R.; Campo, D.; Hoeschele, G.; Parilla, Philip A.; Siegel, N. P.; Toberer, Eric S.; Ginley, David S.

    2017-06-27

    We are developing a novel concentrating solar electricity-generating technology that is both modular and dispatchable. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) uses concentrated solar flux to generate high-temperature thermal energy, which directly converts to electricity via thermoelectric generators (TEGs), stored within a phase-change material (PCM) for electricity generation at a later time, or both allowing for simultaneous charging of the PCM and electricity generation. STEALS has inherent features that drive its cost-competitive scale to be much smaller than current commercial concentrating solar power (CSP) plants. Most obvious is modularity of the solid-state TEG, which favors smaller scales in the kilowatt range as compared to CSP steam turbines, which are minimally 50 MWe for commercial power plants. Here, we present techno-economic and market analyses that show STEALS can be a cost-effective electricity-generating technology with particular appeal to small-scale microgrid applications. We evaluated levelized cost of energy (LCOE) for STEALS and for a comparable photovoltaic (PV) system with battery storage. For STEALS, we estimated capital costs and the LCOE as functions of the type of PCM including the use of recycled aluminum alloys, and evaluated the cost tradeoffs between plasma spray coatings and solution-based boron coatings that are applied to the wetted surfaces of the PCM subsystem. We developed a probabilistic cost model that accounts for uncertainties in the cost and performance inputs to the LCOE estimation. Our probabilistic model estimated LCOE for a 100-kWe STEALS system that had 5 hours of thermal storage and 8-10 hours of total daily power generation. For these cases, the solar multiple for the heliostat field varied between 1.12 and 1.5. We identified microgrids as a likely market for the STEALS system. We characterized microgrid markets in terms of nominal power, dispatchability, geographic location, and

  4. Solar thermoelectricity via advanced latent heat storage: A cost-effective small-scale CSP application

    Science.gov (United States)

    Glatzmaier, G. C.; Rea, J.; Olsen, M. L.; Oshman, C.; Hardin, C.; Alleman, J.; Sharp, J.; Weigand, R.; Campo, D.; Hoeschele, G.; Parilla, P. A.; Siegel, N. P.; Toberer, E. S.; Ginley, D. S.

    2017-06-01

    We are developing a novel concentrating solar electricity-generating technology that is both modular and dispatchable. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) uses concentrated solar flux to generate high-temperature thermal energy, which directly converts to electricity via thermoelectric generators (TEGs), stored within a phase-change material (PCM) for electricity generation at a later time, or both allowing for simultaneous charging of the PCM and electricity generation. STEALS has inherent features that drive its cost-competitive scale to be much smaller than current commercial concentrating solar power (CSP) plants. Most obvious is modularity of the solid-state TEG, which favors smaller scales in the kilowatt range as compared to CSP steam turbines, which are minimally 50 MWe for commercial power plants. Here, we present techno-economic and market analyses that show STEALS can be a cost-effective electricity-generating technology with particular appeal to small-scale microgrid applications. We evaluated levelized cost of energy (LCOE) for STEALS and for a comparable photovoltaic (PV) system with battery storage. For STEALS, we estimated capital costs and the LCOE as functions of the type of PCM including the use of recycled aluminum alloys, and evaluated the cost tradeoffs between plasma spray coatings and solution-based boron coatings that are applied to the wetted surfaces of the PCM subsystem. We developed a probabilistic cost model that accounts for uncertainties in the cost and performance inputs to the LCOE estimation. Our probabilistic model estimated LCOE for a 100-kWe STEALS system that had 5 hours of thermal storage and 8-10 hours of total daily power generation. For these cases, the solar multiple for the heliostat field varied between 1.12 and 1.5. We identified microgrids as a likely market for the STEALS system. We characterized microgrid markets in terms of nominal power, dispatchability, geographic location, and

  5. Tingkat Insidensi Malaria di Wilayah Pemanasan Kelambu Berinsektisida Tahan Lama dan Wilayah Kontrol (MALARIA INCIDENCE RATE OF HEAT ASSISTED REGENERATION LONG LASTING INSECTICIDAL NETS AREA AND CONTROL

    Directory of Open Access Journals (Sweden)

    Etih Sudarnika

    2012-03-01

    Full Text Available Long lasting insecticidal nets (LLIN is one effective way to prevent malaria. Permethrin treatedLLIN is one type of LLIN which is recommended by WHO. Several studies have shown that these types ofLLIN requiring heat assisted regeneration after washing to enhance the biological activity of insecticidethat contained in the LLIN fibers. This study aimed to compare the incidence rates of malaria in childrenunder five years old who live in the intervention area (where the heat assisted regeneration on LLIN afterwashing was applied and control area (where the heat assisted regeneration on LLIN after washing wasnot applied. Data of malaria cases was collected from laboratory log book at all health centers in BangkaDistrict, in the period of June June 2007 until July 2008. Data were analyzed with Poisson regressionmodels. The results showed that the incidence rate of malaria in children under five years old was notsignificantly different between the treatment and control areas.

  6. Response surface method optimization of V-shaped fin assisted latent heat thermal energy storage system during discharging process

    Directory of Open Access Journals (Sweden)

    Sina Lohrasbi

    2016-09-01

    Full Text Available Latent Heat Thermal Energy Storage Systems (LHTESS containing Phase Change Material (PCM are used to establish balance between energy supply and demand. PCMs have high latent heat but low thermal conductivity, which affects their heat transfer performance. In this paper, a novel fin array has been optimized by multi-objective Response Surface Method (RSM based on discharging process of PCM, and then this fin configuration is applied on LHTESS, and comparison between full discharging time by applying this fin array and LHTESS with other fin structures has been carried out. The employed numerical method in this paper is Standard Galerkin Finite Element Method. Adaptive grid refinement is used to solve the equations. Since the enhancement technique, which has been employed in the present study reduces the employed PCM mass, maximum energy storage capacity variations have been considered. Therefore phase change expedition and maximum energy storage capacity have been considered as the objectives of optimization and the importance of second objective is indicated which is proposed as the novelty here. Results indicate that considering maximum energy storage capacity as the objective of optimization procedure leads to efficient shape design of LHTESS. Also employing optimized V-shaped fin in LHTESS, expedites discharging process considerably in comparison with the LHTESS without fin.

  7. Chlorophylls and carotenoids of kiwifruit puree are affected similarly or less by microwave than by conventional heat processing and storage.

    Science.gov (United States)

    Benlloch-Tinoco, María; Kaulmann, Anouk; Corte-Real, Joana; Rodrigo, Dolores; Martínez-Navarrete, Nuria; Bohn, Torsten

    2015-11-15

    The impact of microwave (1000 W - 340 s) and conventional heat (97 °C - 30s) pasteurisation and storage (4, 10, 22 °C for up to 63 d) on total and individual carotenoids and chlorophylls in kiwifruit puree was evaluated. Bioaccessibility of carotenoids, before and after pasteurisation and storage, was also studied. Microwaves and conventional heating led to marked changes in the chlorophyll (42-100% losses) and carotenoid (62-91% losses) content. First- and second-order kinetics appropriately explained the degradation of total carotenoids and chlorophylls over time, respectively. Pasteurised samples showed significantly (p < 0.05) enhanced stability of these pigments, with microwaves (k = 0.007-0.031100 g mg(-1) day(-1) at 4-22 °C) promoting chlorophyll stability to a greater extent than conventional heating (k = 0.0015-0.034100 g mg(-1) day(-1) at 4-22 °C). Bioaccessibility of carotenoids remained (p < 0.05) unaffected by processing and storage. These results highlighted that the pigment composition of microwaved kiwifruit was more similar to that of the fresh fruit and better preserved during storage. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Melting and solidification characteristics of a mixture of two types of latent heat storage material in a vessel

    Science.gov (United States)

    Yu, JikSu; Horibe, Akihiko; Haruki, Naoto; Machida, Akito; Kato, Masashi

    2016-11-01

    In this study, we investigated the fundamental melting and solidification characteristics of mannitol, erythritol, and their mixture (70 % by mass mannitol: 30 % by mass erythritol) as potential phase-change materials (PCMs) for latent heat thermal energy storage systems, specifically those pertaining to industrial waste heat, having temperatures in the range of 100-250 °C. The melting point of erythritol and mannitol, the melting peak temperature of their mixture, and latent heat were measured using differential scanning calorimetry. The thermal performance of the mannitol mixture was determined during melting and solidification processes, using a heat storage vessel with a pipe heat exchanger. Our results indicated phase-change (fusion) temperatures of 160 °C for mannitol and 113 and 150 °C for the mannitol mixture. Nondimensional correlation equations of the average heat transfer during the solidification process, as well as the temperature and velocity efficiencies of flowing silicon oil in the pipe and the phase-change material (PCM), were derived using several nondimensional parameters.

  9. Identification of sixteen peptides reflecting heat and/or storage induced processes by profiling of commercial milk samples.

    Science.gov (United States)

    Ebner, Jennifer; Baum, Florian; Pischetsrieder, Monika

    2016-09-16

    Peptide profiles of different drinking milk samples were examined to study how the peptide fingerprint of milk reflects processing conditions. The combination of a simple and fast method for peptide extraction using stage tips and MALDI-TOF-MS enabled the fast and easy generation and relative quantification of peptide fingerprints for high-temperature short-time (HTST), extended shelf life (ESL) and ultra-high temperature (UHT) milk of the same dairies. The relative quantity of 16 peptides changed as a function of increasing heat load. Additional heating experiments showed that among those, the intensity of peptide β-casein 196-209 (m/z 1460.9Da) was most heavily influenced by heat treatment indicating a putative marker peptide for milk processing conditions. Storage experiments with HTST- and UHT milk revealed that the differences between different types of milk samples were not only caused by the heating process. Relevant was also the proteolytic activity of enzymes during storage, which were differently influenced by the heat treatment. These results indicate that the peptide profile may be suitable to monitor processing as well as storage conditions of milk. In the present study, peptide profiling of different types of milk was carried out by MALDI-TOF-MS after stage-tip extraction and relative quantification using an internal reference peptide. Although MALDI-TOF-MS covers only part of the peptidome, the method is easy and quick and is, therefore, suited for routine analysis to address several aspects of food authenticity. Using this method, 16 native peptides were detected in milk that could be modulated by different industrial processes. Subsequent heating and storage experiments with pasteurized and UHT milk confirmed that these peptides are indeed related to the production or storage conditions of the respective products. Furthermore, the heating experiments revealed one peptide, namely the β-casein-derived sequence β-casein 196-209, which underwent

  10. The utilization of the storage of thermal energy in buildings. Underground heat storages - thermic simulation and profitability; Termisen energian varastoinnin hyvaeksikaeyttoemahdollisuudet rakennusten laemmityksessae ja jaeaehdytyksessae. Maanalaiset varastot - laempoetekninen simulointi ja taloudellinen kannattavuus

    Energy Technology Data Exchange (ETDEWEB)

    Suokas, M.; Heinonen, J.; Karola, A.; Laine, T.; Siren, K.

    1998-12-31

    Interest in different sources of free energy has significantly increased due to the possibility to decrease the consumption of fossil fuels and nuclear power. This can be reached, for example, with waste heat recovery and by utilising natural heat and cool energy sources. The main problem is that the supply and use of energy do not encounter and this causes a need for thermal energy storage. The earlier heat storage systems have utilised compressor heat pumps because the temperature levels of heat storages are not high enough for the ordinary heating and cooling systems. The disadvantage is the complexity of these systems which leads to increasing building costs. Therefore, this study deals with systems of low temperature levels used mainly for cooling purposes. The aim was to find out their usability, savings and profitability. The function and energy consumption of systems were simulated with models of buildings, soil heat storage and climate. The soil model simulates heat dynamic behaviour of the masses of soil. With the climate model it was possible to simulate transient heat losses of the storage and building. It was also possible to simulate various climatic conditions by changing input data of the climate model. In the simulated systems the emphasis is on the production of cooling energy by utilising the low temperature of the ground. The systems consist of heat storage and building. The cooling energy will be charged in winter to the storage when the heat energy charged in summer will be transferred to the supply air of ventilating unit. After the energy simulations the investment and usage costs of this kind of systems were compared with costs of ordinary compressor cooling systems. The buildings studied were an imaginary LVIS 2000 office building and the Messukeskus in Helsinki which is a large hall built for exhibitions. The types of soil were wet clay and granite. The LVIS 2000 office building needs a rock heat storage with capacity of 8 000-30 000 m

  11. Direct-contact high-temperature thermal energy storage heat exchanger. Final subcontract report

    Energy Technology Data Exchange (ETDEWEB)

    Alario, J.; Brown, R.

    1983-09-01

    A 10-kWh scale model high-temperature direct-contact latent-heat-exchange thermal energy storage system was designed and fabricated. A research program was structured in three separate phases to permit: Phase I - the inspection and evaluation of the origin al hardware, which suffered extensive corrosion and damage in a previous experimental program; Phase II - redesign and fabrication of a modified system; and Phase III - detailed test evaluation. On the basis of the findings in Phase I, the design was modified to eliminate previous deficiencies. A test plan was also prepared that contained detailed information concerning instrumentation (type and location), measured parameters, and equipment operating procedures. Phase II entailed component procurement and fabrication, system assembly, and instrumentation. At the end of Phase II, the system was in a ready-for-test condition but the program was terminated before the start of the Phase III test evaluation. Since testing was never implemented, this report presents only the results for the design and fabrication phases of the program.

  12. The roles of thermal insulation and heat storage in the energy performance of the wall materials: a simulation study.

    Science.gov (United States)

    Long, Linshuang; Ye, Hong

    2016-04-07

    A high-performance envelope is the prerequisite and foundation to a zero energy building. The thermal conductivity and volumetric heat capacity of a wall are two thermophysical properties that strongly influence the energy performance. Although many case studies have been performed, the results failed to give a big picture of the roles of these properties in the energy performance of an active building. In this work, a traversal study on the energy performance of a standard room with all potential wall materials was performed for the first time. It was revealed that both heat storage materials and insulation materials are suitable for external walls. However, the importances of those materials are distinct in different situations: the heat storage plays a primary role when the thermal conductivity of the material is relatively high, but the effect of the thermal insulation is dominant when the conductivity is relatively low. Regarding internal walls, they are less significant to the energy performance than the external ones, and they need exclusively the heat storage materials with a high thermal conductivity. These requirements for materials are consistent under various climate conditions. This study may provide a roadmap for the material scientists interested in developing high-performance wall materials.

  13. A life cycle cost analysis of large-scale thermal energy storage technologies for buildings using combined heat and power

    Energy Technology Data Exchange (ETDEWEB)

    Gaine, K.; Duffy, A.

    2010-07-01

    Full text: Buildings account for approximately 40% of energy consumption and greenhouse gas (GHG) emissions in developed economies, of which approximately 55% of building energy is used for heating and cooling. The reduction of building-related GHG emissions is a high international policy priority. For this reason and because there are many technical solutions for this, these polices should involve significant improvements in the uptake of small-scale energy efficient (EE) systems. However the widespread deployment of many technologies, must overcome a number of barriers, one of which is a temporal (diurnal or seasonal) mismatch between supply and demand. For example, in office applications, peak combined heat and power (CHP) thermal output may coincide with peak electrical demand in the late morning or afternoon, whereas heating may be required early in the morning. For this reason, cost-effective thermal storage solutions have the potential to improve financial performance, while simultaneously reducing associated GHG emissions. The aim of this paper is to identify existing thermal energy storage (TES) technologies and to present and asses the economic and technical performance of each for a typical large scale mixed development. Technologies identified include: Borehole Thermal Energy Storage (BTES); Aquifer Thermal Energy Storage (ATES); Pitt Thermal Energy Storage (PTES) and Energy Piles. Of these the most appropriate for large scale storage in buildings were BTES and ATES because of they are relatively cheap and are installed under a building and do not use valuable floor area A Heat transfer analyses and system simulations of a variety of BTES systems are carried out using a Finite Element Analysis package (ANSYS) and energy balance simulation software (TRNSYS) is to determine the optimal system design. Financial models for each system are developed, including capital, installation, running and maintenance costs. Using this information the unit costs of

  14. Heat-energy storage through semi-opened circulation into low-permeability hard-rock aquifers

    Science.gov (United States)

    Pettenati, Marie; Bour, Olivier; Ausseur, Jean-Yves; de Dreuzy, Jean-Raynald; de la Bernardie, Jérôme; Chatton, Eliot; Lesueur, Hervé; Bethencourt, Lorine; Mougin, Bruno; Aquilina, Luc; Koch, Florian; Dewandel, Benoit; Boisson, Alexandre; Mosser, Jean-François; Pauwels, Hélène

    2016-04-01

    In low-permeability environments, the solutions of heat storage are still limited to the capacities of geothermal borehole heat exchangers. The ANR Stock-en-Socle project explores the possibilities of periodic storage of sensitive heat1 in low-permeability environments that would offer much better performance than that of borehole heat exchangers, especially in terms of unit capacity. This project examines the storage possibilities of using semi-open water circulation in typically a Standing Column Well (SCW), using the strong heterogeneity of hard-rock aquifers in targeting the least favorable areas for water resources. To solve the main scientific issues, which include evaluating the minimum level of permeability required around a well as well as its evolution through time (increase and decrease) due to water-rock interaction processes, the study is based on an experimental program of fieldwork and modelling for studying the thermal, hydraulic and geochemical processes involved. This includes tracer and water-circulation tests by injecting hot water in different wells located in distinct hard-rock settings (i.e. granite and schist) in Brittany, Ploemeur (H+ observatory network) and Naizin. A numerical modelling approach allows studying the effects of permeability structures on the storage and heat-recovery capacities, whereas the modelling of reactive transfers will provide an understanding of how permeability evolves under the influence of dissolution and precipitation. Based on the obtained results, technical solutions will be studied for constructing a well of the SCW type in a low-permeability environment. This work will be completed by a technical and economic feasibility study leading to an investment and operations model. This study aims to describe the suitability of SCW storage for shallow geothermal energy. In order to reach these objectives, Stock-en-Socle is constructed around a public/private partnership between two public research organizations, G

  15. Numerical Simulation on Flow and Heat Transfer Performance of Air-cooler for a Natural Gas Storage Compressor Unit

    Science.gov (United States)

    Liu, Biyuan; Zhang, Feng; Ma, Zenghui; Zheng, Zilong; Feng, Jianmei

    2017-08-01

    Heat transfer efficiency has been a key issue for large size air coolers with the noise reducers used in natural gas storage compressor unit, especially operated in summer with cooling air at a high temperature. The 3-D numerical simulation model of the whole air cooler was established to study the flow field characteristic with different inlet and outlet structures by CFD software. The system pressure loss distributions were calculated. The relationship was obtained among heat exchange efficiency, resistance loss, and the structure of air cooler, the results presented some methods to improve cooling air flow rate and heat exchange efficiency. Based on the results, some effective measures were proposed to improve heat exchanger efficiency and were implemented in the actual operation unit.

  16. Annual Performance of a Two-Speed, Dedicated Dehumidification Heat Pump in the NIST Net-Zero Energy Residential Test Facility.

    Science.gov (United States)

    Payne, W Vance

    2016-01-01

    A 2715 ft2 (252 m2), two story, residential home of the style typical of the Gaithersburg, Maryland area was constructed in 2012 to demonstrate technologies for net-zero energy (NZE) homes (or ZEH). The NIST Net-Zero Energy Residential Test Facility (NZERTF) functions as a laboratory to support the development and adoption of cost-effective NZE designs, technologies, construction methods, and building codes. The primary design goal was to meet the comfort and functional needs of the simulated occupants. The first annual test period began on July 1, 2013 and ended June 30, 2014. During the first year of operation, the home's annual energy consumption was 13039 kWh (4.8 kWh ft-2, 51.7 kWh m-2), and the 10.2 kW solar photovoltaic system generated an excess of 484 kWh. During this period the heating and air conditioning of the home was performed by a novel air-source heat pump that utilized a reheat heat exchanger to allow hot compressor discharge gas to reheat the supply air during a dedicated dehumidification mode. During dedicated dehumidification, room temperature air was supplied to the living space until the relative humidity setpoint of 50% was satisfied. The heat pump consumed a total of 6225 kWh (2.3 kWh ft-2, 24.7 kWh m-2) of electrical energy for cooling, heating, and dehumidification. Annual cooling efficiency was 10.1 Btu W-1h-1 (2.95 W W-1), relative to the rated SEER of the heat pump of 15.8 Btu W-1h-1 (4.63 W W-1). Annual heating efficiency was 7.10 Btu W-1h-1 (2.09 W W-1), compared with the unit's rated HSPF of 9.05 Btu W-1h-1 (2.65 W W-1). These field measured efficiency numbers include dedicated dehumidification operation and standby energy use for the year. Annual sensible heat ratio was approximately 70%. Standby energy consumption was 5.2 % and 3.5 % of the total electrical energy used for cooling and heating, respectively.

  17. New Carbon-Based Porous Materials with Increased Heats of Adsorption for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Snurr, Randall Q.; Hupp, Joseph T.; Kanatzidis, Mercouri G.; Nguyen, SonBinh T.

    2014-11-03

    . Modeling played an important role throughout the project. For example, we used molecular simulations to determine that the optimal isosteric heat of adsorption (Qst) for maximum hydrogen delivery using MOFs is approximately 20 kJ/mol. If the heat of adsorption is too low, little hydrogen is adsorbed. If the heat of adsorption is too high, it is difficult to recover the hydrogen at the desorption pressure. The results supported the major premise of this project that increasing Qst for MOFs with large surface areas is required to attain current hydrogen storage targets in terms of deliverable capacity.

  18. Optimal Design of Cogeneration Systems in Industrial Plants Combined with District Heating/Cooling and Underground Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Vincenzo Dovì

    2011-12-01

    Full Text Available Combined heat and power (CHP systems in both power stations and large plants are becoming one of the most important tools for reducing energy requirements and consequently the overall carbon footprint of fundamental industrial activities. While power stations employ topping cycles where the heat rejected from the cycle is supplied to domestic and industrial consumers, the plants that produce surplus heat can utilise bottoming cycles to generate electrical power. Traditionally the waste heat available at high temperatures was used to generate electrical power, whereas energy at lower temperatures was either released to the environment or used for commercial or domestic heating. However the introduction of new engines, such as the ones using the organic Rankine cycle, capable of employing condensing temperatures very close to the ambient temperature, has made the generation of electrical power at low temperatures also convenient. On the other hand, district heating is becoming more and more significant since it has been extended to include cooling in the warm months and underground storage of thermal energy to cope with variable demand. These developments imply that electric power generation and district heating/cooling may become alternative and not complementary solutions for waste energy of industrial plants. Therefore the overall energy management requires the introduction of an optimisation algorithm to select the best strategy. In this paper we propose an algorithm for the minimisation of a suitable cost function, for any given variable heat demand from commercial and domestic users, with respect to all independent variables, i.e., temperatures and flowrates of warm fluid streams leaving the plants and volume and nature of underground storage. The results of the preliminary process integration analysis based on pinch technology are used in this algorithm to provide bounds on the values of temperatures.

  19. Eutectic mixtures of some fatty acids for latent heat storage: Thermal properties and thermal reliability with respect to thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Ahmet [Department of Chemistry, Gaziosmanpasa University, 60240 Tokat (Turkey)]. E-mail: asari@gop.edu.tr

    2006-06-15

    Accelerated thermal cycle tests have been conducted to study the change in melting temperatures and latent heats of fusion of the eutectic mixtures of lauric acid (LA)-myristic acid (MA), lauric acid (LA)-palmitic acid (PA) and myristic acid (MA)-stearic acid (SA) as latent heat storage materials. The thermal properties of these materials were determined by the differential scanning calorimetry (DSC) analysis method. The thermal reliability of the eutectic mixtures after melt/freeze cycles of 720, 1080 and 1460 was also evaluated using the DSC curves. The accelerated thermal cycle tests indicate that the melting temperatures usually tend to decrease, and the variations in the latent heats of fusion are irregular with increasing number of thermal cycles. Moreover, the probable reasons for the change in thermal properties of the eutectic mixtures after repeated thermal cycles were investigated. Fourier Transform Infrared (FT-IR) spectroscopic analysis indicates that the accelerated melt/freeze processes do not cause any degradation in the chemical structure of the mixtures. The change in thermal properties of the eutectic mixtures with increasing number of thermal cycles is only because of the presence of certain amounts of impurities in the fatty acids used in their preparation. It is concluded that the tested eutectic mixtures have reasonable thermal properties and thermal reliability as phase change materials (PCMs) for latent heat storage in any solar heating applications that include a four year utilization period.

  20. Core Flooding Experiments and Reactive Transport Modeling of Seasonal Heat Storage in the Hot Deep Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, Hanne D.; Kjøller, Claus; Fabricius, Ida Lykke

    2017-01-01

    Seasonal storage of excess heat in hot deep aquifers is considered to optimize the usage of commonly available energy sources. The chemical effects of heating the Gassum Sandstone Formation to up to 150 degrees C is investigated by combining laboratory core flooding experiments with petrographic...... process at 150 degrees C, resulting in a significant increase in the aqueous silicium concentration. At temperatures,100 degrees C, the silicium concentration was controlled by a quasi-stationary state between feldspar dissolution and kaolinite precipitation whereas the concentration was kinetically...

  1. BWR spent fuel storage cask performance test. Volume 2. Pre- and post-test decay heat, heat transfer, and shielding analyses

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, L.E.; Lombardo, N.J.; Heeb, C.M.; Jenquin, U.P.; Michener, T.E.; Wheeler, C.L.; Creer, J.M.; McCann, R.A.

    1986-06-01

    This report describes the decay heat, heat transfer, and shielding analyses conducted in support of performance testing of a Ridhihalgh, Eggers and Associates REA 2033 boiling water reactor (BWR) spent fuel storage cask. The cask testing program was conducted for the US Department of Energy (DOE) Commercial Spent Fuel Management Program by the Pacific Northwest Laboratory (PNL) and by General Electric at the latters' Morris Operation (GE-MO) as reported in Volume I. The analyses effort consisted of performing pretest calculations to (1) select spent fuel for the test; (2) symmetrically load the spent fuel assemblies in the cask to ensure lateral symmetry of decay heat generation rates; (3) optimally locate temperature and dose rate instrumentation in the cask and spent fuel assemblies; and (4) evaluate the ORIGEN2 (decay heat), HYDRA and COBRA-SFS (heat transfer), and QAD and DOT (shielding) computer codes. The emphasis of this second volume is on the comparison of code predictions to experimental test data in support of the code evaluation process. Code evaluations were accomplished by comparing pretest (actually pre-look, since some predictions were not completed until testing was in progress) predictions with experimental cask testing data reported in Volume I. No attempt was made in this study to compare the two heat transfer codes because results of other evaluations have not been completed, and a comparison based on one data set may lead to erroneous conclusions.

  2. Domestic olivine vs magnesite as a thermal-energy-storage material: performance comparisons for electrically heated room-size units in accordance with ASHRAE Standard 94. 2

    Energy Technology Data Exchange (ETDEWEB)

    Laster, W.R.; Schoenhals, R.J.; Gay, B.M.; Palmour, H. III

    1982-01-01

    Electrically heated thermal-energy-storage (TES) heaters employing high-heat-capacity ceramic refractories for sensible heat storage have been in use in Europe for several years. With these heaters, low cost off-peak electrical energy is stored by heating a storage core composed of ceramic material to approximately 800/sup 0/C. During the peak period, no electrical energy is used as the building heating needs are supplied by extracting the stored heat from the core by forced air circulation. Recently significant interest in the use of off-peak TES units in the US has occured, leading to the search for a domestic supply of high heat capacity ceramic refractory material. North Carolina's extensive but under-utilized supply of refractory grade olivine has been proposed as a source of storage material for these units. In this paper, the suitability of North Carolina olivine for heat-storage applications is assessed by comparing its thermal performance with that of European materials. Using the method of ASHRAE Standard 94.2, the thermal performance of two small room-sized commercially available TES units was determined experimentally with two different storage materials, North Carolina olivine and German magnesite. Comparisons between the two materials are made and conclusions are drawn.

  3. A model predictive framework of Ground Source Heat Pump coupled with Aquifer Thermal Energy Storage System in heating and cooling equipment of a building : Use it or loose it

    NARCIS (Netherlands)

    Rostampour Samarin, V.; Bloemendal, J.M.; Keviczky, T.

    2017-01-01

    This paper presents a complete model of a building heating and cooling equipment and a ground source heat pump (GSHP) coupled with an aquifer thermal energy storage (ATES) system. This model contains detailed
    mathematical representations of building thermal dynamics, ATES system dynamics, heat

  4. A Model Predictive Framework of Ground Source Heat Pump coupled with Aquifer Thermal Energy Storage System in Heating and Cooling Equipment of a Building : Use it or loose it

    NARCIS (Netherlands)

    Rostampour Samarin, V.; Bloemendal, J.M.; Keviczky, T.

    2017-01-01

    This paper presents a complete model of a building heating and cooling equipment and a ground source heat pump (GSHP) coupled with an aquifer thermal energy storage (ATES) system. This model contains detailed
    mathematical representations of building thermal dynamics, ATES system dynamics, heat

  5. An optimization methodology for the design of renewable energy systems for residential net zero energy buildings with on-site heat production

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2011-01-01

    energy supply systems for residential NZEB involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system......The concept of net zero energy buildings (NZEB) has received increased attention throughout the last years. A well adapted and optimized design of the energy supply system is crucial for the performance of such buildings. This paper aims at developing a method for the optimal sizing of renewable...

  6. The effects of different air velocities on heat storage and body temperature in humans cycling in a hot, humid environment.

    Science.gov (United States)

    Saunders, A G; Dugas, J P; Tucker, R; Lambert, M I; Noakes, T D

    2005-03-01

    The purposes of this study were to determine (i) the effects of different facing air velocities on body temperature and heat storage during exercise in hot environmental conditions and (ii) the effects of ingesting fluids at two different rates on thermoregulation during exercise in hot conditions with higher air velocities. On five occasions nine subjects cycled for 2 h at 33.0 +/- 0.4 degrees C with a relative humidity of 59 +/- 3%. Air velocity was maintained at 0.2 km h(-1) (0 WS), 9.9 +/- 0.3 km h(-1) (10 WS), 33.3 +/-2.2 km h(-1) (100 WS) and 50.1 +/- 3.2 km h(-1) (150 WS) while subjects replaced 58.8 +/- 6.8% of sweat losses. In the fifth condition, air velocity was maintained at 33.7 +/- 2.2 km h(-1) and subjects replaced 80.0 +/- 6.8% of sweat losses (100.80 WS). Heat storage, body temperature and rating of perceived exertion were higher in 0 and 10 WS compared with all other conditions. There were no differences in any measured variable between 100 and 150 WS, or between 100 and 100.80 WS. Thus, the evaporative capacity of the environment is increased with higher air velocities, reducing heat storage and body temperature. At higher air velocities, a higher rate of fluid ingestion did not influence heat storage, body temperature or sweat rate. The finding of previous laboratory studies showing a beneficial effect of high rates of fluid ingestion on thermoregulation during exercise in hot, humid, windstill conditions cannot be extrapolated to out-of-doors exercise in which facing air velocities are seldom lower than the athlete's rate of forward progression.

  7. Thermal and economic assessment of ground-coupled storage for residential solar heat pump systems

    Science.gov (United States)

    Choi, M. K.; Morehouse, J. H.

    1980-11-01

    This study performed an analysis of ground-coupled stand-alone and series configured solar-assisted liquid-to-air heat pump systems for residences. The year-round thermal performance of these systems for space heating, space cooling, and water heating were determined by simulation and compared against non-ground-coupled solar heat pump systems as well as conventional heating and cooling systems in three geographic locations: Washington, D.C., Fort Worth, Tex., and Madison, Wis. The results indicate that without tax credits a combined solar/ground-coupled heat pump system for space heating and cooling is not cost competitive with conventional systems. Its thermal performance is considerably better than non-ground-coupled solar heat pumps in Forth Worth. Though the ground-coupled stand-alone heat pump provides 51% of the heating and cooling load with non-purchased energy in Forth Worth, its thermal performance in Washington and Madison is poor.

  8. SolNet

    DEFF Research Database (Denmark)

    Jordan, Ulrike; Vajen, Klaus; Bales, Chris

    2014-01-01

    SolNet, founded in 2006, is the first coordinated International PhD education program on Solar Thermal Engineering. The SolNet network is coordinated by the Institute of Thermal Engineering at Kassel University, Germany. The network offers PhD courses on solar heating and cooling, conference...

  9. Food matrices and cell conditions influence survival of Lactobacillus rhamnosus GG under heat stresses and during storage.

    Science.gov (United States)

    Endo, Akihito; Teräsjärvi, Johanna; Salminen, Seppo

    2014-03-17

    The present study evaluated impact of moisture content and cell conditions on survival of probiotic strain, Lactobacillus rhamnosus GG, under lethal heat stresses and during long-term storage using freeze-dried cells and oils as matrices. Viable cell counts of freeze-dried L. rhamnosus GG cells suspended in oils had only 1-log-reduction after 5min at 80°C and approximately 3-log-reduction after 20min, while no or very few viable cells were recorded for freeze dried cells suspended in buffer and cultured cells in oils. Surprisingly, freeze-dried cells suspended in oils still contained 4.3 to 6.7logCFU/ml after 5min at 95°C. Long-term storage study indicated that freeze-dried cells suspended in oils kept viable conditions for 4months, and a loss of the viability was only 0.3 to 0.6logCFU/ml. Viable cell counts of cultured cells suspended in oils were not present after 3days to 3months. These results clearly indicate that moisture and cell conditions have a great impact on survival of probiotics under severe heat stress in processing and during long-term storage. Combination of freeze-dried cells and oils as carrier provides beneficial options to preserve viability of probiotics in food processes and storage. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Influence of storage and heating on protein glycation levels of processed lactose-free and regular bovine milk products.

    Science.gov (United States)

    Milkovska-Stamenova, Sanja; Hoffmann, Ralf

    2017-04-15

    Thermal treatment preserves the microbiological safety of milk, but also induces Maillard reactions modifying for example proteins. The purpose of this study was evaluating the influence of consumer behaviors (storage and heating) on protein glycation degrees in bovine milk products. Lactosylation and hexosylation sites were identified in ultra-high temperature (UHT), lactose-free pasteurized, and lactose-free UHT milk (ULF) and infant formula (IF) using tandem mass spectrometry (electron transfer dissociation). Overall, 303 lactosylated and 199 hexosylated peptides were identified corresponding to 170 lactosylation (31 proteins) and 117 hexosylation sites (25 proteins). In quantitative terms, storage increased lactosylation up to fourfold in UHT and IF and hexosylation up to elevenfold in ULF and threefold in IF. These levels increased additionally twofold when the stored samples were heated (40°C). In conclusion, storage and heating appear to influence protein glycation levels in milk at similar or even higher degrees than industrial processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Multifunctional wall coating combining photocatalysis, self-cleaning and latent heat storage

    Science.gov (United States)

    Lucas, S. S.; Barroso de Aguiar, J. L.

    2018-02-01

    Mortars, one of the most common construction materials, have not received any substantial modification for many decades. This has changed in recent years; new compositions are now being developed, with new properties, using nano-additives, fibres and capsules. In this work, surfaces with new and innovative functionalities that promote energy savings and improve air quality have been developed and studied. Incorporation of phase change materials (PCM) and titanium dioxide (TiO2) nanoparticles in construction products is currently under study by different research groups. However, these studies only address their incorporation separately. Adding new additives into the mortar’s matrix can be complex—due to microstructural modifications that will influence both fresh and hardened state properties. Moving from a single additive to multiple additions, as in this study, increases the system’s complexity. Only with a good understanding of the microstructural properties, it is possible to add multiple additives (including nano and microparticles) to mortars, without damaging its final quality. This work demonstrates that a higher additive content is not always a guarantee of better results; lower additions can often provide a better compromise between performance and final mechanical properties. The results presented in this paper confirmed this and show that combining PCM microcapsules and TiO2 nanoparticles open a new path in the development of mortars with multiple functionalities. In this study, a new material with depolluting, self-cleaning and heat storage was created. For the development of new and innovative mortars, a proper balance of multiple additives, supported by the study of microstructural changes, can lead to an optimization of the compositions, ensuring that the mortar’s final properties are not affected.

  12. Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003; Programme 'Solaire actif - Chaleur et Stockage de chaleur'. Activites et projets en 2003

    Energy Technology Data Exchange (ETDEWEB)

    Hadorn, J.-C. [Base Consultants, Geneva (Switzerland); Renaud, P. [Planair SA, La Sagne (Switzerland)

    2003-07-01

    In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD

  13. The underground heat storage for solar-assisted district heating in Neckarsulm. First measuring results; Der Erdsonden-Waermespeicher fuer die solarunterstuetzte Nahwaermeversorgung in Neckarsulm. Erste Messergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Seiwald, H.; Hahne, E. [Stuttgart Univ. (Germany). Inst. fuer Thermodynamik und Waermetechnik

    1998-12-31

    A solar-assisted district heating system with seasonal underground heat storage is currently under construction in Neckarsulm (Baden-Wurttemberg). In the new residential area approximately 1,300 flats are going to be built during the next years. The overall energy demand (hot water and space heating) is supposed to be covered by 50% with solar energy. During the first phase the project will be subsidised in the frame of the BMBF programme `Solarthermie 2000, Teilprogramm III`. A solar plant consisting of 2,700 square metres of collectors, a buffer tank (100 cubic metre) and an underground heat storage with a volume of approx. 20,000 cubic metres will be constructed by the end of 1998. It will be the first plant in Germany where thermal energy generated of solar energy is stored at high temperatures (up to 80 C) directly in the earth and utilised without a heat pump. (orig.) [Deutsch] In Neckarsulm (Baden-Wuerttemberg) befindet sich derzeit eine solar unterstuetzte Nahwaermeversorgung mit saisonalem Endsonden-Waermespeicher im Aufbau. Im Neubaugebiet Amorbach werden in den naechsten Jahren rund 1300 Wohneinheiten entstehen, deren Gesamtwaermebedarf (Warmwasser und Raumheizung) zu rund 50% mit Sonnenenergie gedeckt werden soll. In der ersten Phase wird das Projekt im Rahmen des BMBF-Programms `Solarthermie 2000, Teilprogramm III` gefoerdert. Bis Ende 1998 wird eine Solaranlage bestehend aus 2.700 m{sup 2} Kollektoren, einem Pufferspeicher (100 m{sup 3}) und einem Endsonden-Waermespeicher mit einem Volumen von ca. 20.000 m{sup 3} erstellt. Damit wird in Deutschland erstmalig eine Anlage realisiert, bei der solar erzeugte Waerme auf hohem Temperaturniveau (bis zu 80 C) direkt im Erdreich gespeichert und ohne Waermepumpe genutzt werden soll. (orig.)

  14. Discovery of Rapid and Reversible Water Insertion in Rare Earth Sulfates: A New Process for Thermochemical Heat Storage.

    Science.gov (United States)

    Hatada, Naoyuki; Shizume, Kunihiko; Uda, Tetsuya

    2017-07-01

    Thermal energy storage based on chemical reactions is a prospective technology for the reduction of fossil-fuel consumption by storing and using waste heat. For widespread application, a critical challenge is to identify appropriate reversible reactions that occur below 250 °C, where abundant low-grade waste heat and solar energy might be available. Here, it is shown that lanthanum sulfate monohydrate La 2 (SO 4 ) 3 ⋅H 2 O undergoes rapid and reversible dehydration/hydration reactions in the temperature range from 50 to 250 °C upon heating/cooling with remarkably small thermal hysteresis (dehydration/hydration behavior. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Numerical performance study of paraffin wax dispersed with alumina in a concentric pipe latent heat storage system

    Directory of Open Access Journals (Sweden)

    Valan Arasu Amirtham

    2013-01-01

    Full Text Available Latent heat energy storage systems using paraffin wax could have lower heat transfer rates during melting/freezing processes due to its inherent low thermal conductivity. The thermal conductivity of paraffin wax can be enhanced by employing high conductivity materials such as alumina (Al2O3. A numerical analysis has been carried out to study the performance enhancement of paraffin wax with nanoalumina (Al2O3 particles in comparison with simple paraffin wax in a concentric double pipe heat exchanger. Numerical analysis indicates that the charge-discharge rates of thermal energy can be greatly enhanced using paraffin wax with alumina as compared with a simple paraffin wax as PCM.

  16. Ground water heat pumps and cooling with ground water basins as seasonal storage; Grundvandsvarmepumper og -koeling med grundvandsmagasiner som saesonlager

    Energy Technology Data Exchange (ETDEWEB)

    2008-04-15

    Ground water temperature is constant all the year round, in Denmark approximately 9 deg. C, which is ideal for a number of cooling purposes including cooling of buildings. The structures in which the ground water flows (sand, gravel and chalk) are efficient for storing coldness and heat over longer periods. By using seasonal storage of low-temperature heat and coldness in ground water layers close to the terrain it is feasible to reach profitable energy savings of up to 90% for cooling and heating of e.g. hotels, airports, shopping malls, office buildings and other larger buildings. At the same time the large energy savings means major reduction of CO{sub 2} emissions. (BA)

  17. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Balyk, Olexandr

    2013-01-01

    Individual compression heat pumps constitute a potentially valuable resource in supporting wind power integration due to their economic competitiveness and possibilities for flexible operation. When analysing the system benefits of flexible heat pump operation, effects on investments should be ta...

  18. Towards development of a prototype high-temperature latent heat storage unit as an element of a RES-based energy system (part 1)

    National Research Council Canada - National Science Library

    K Bogucka-Bykuc; W Wlosinski; S Bykuc

    2014-01-01

    ...) plants utilizing renewable energy sources (RES) for residential applications. Next, a paper introduces initial research carried out in IMP PAN in Gdansk, Poland, aimed at development of a prototype latent heat storage unit...

  19. Solar-hydrogen energy systems: an authoritative review of water-splitting systems by solar beam and solar heat : hydrogen production, storage, and utilisation

    National Research Council Canada - National Science Library

    Ōta, Tokio

    1979-01-01

    ... An Authoritative Review of Watersplitting Systems by Solar Beam and Solar Heat: Hydrogen Production, Storage and Utilisation edited by TOKIO OHTA Professor of Materials Science and Energy System Yoko...

  20. Status seminar `98: Solar-supported district heating with seasonal heat storage. Status report `98; Status-Seminar `98: Solarunterstuetzte Nahwaermeversorgung - Saisonale Waermespeicherung. Statusbericht `98

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This status report refers to the BMBF (Federal Ministry for Education, Science, Research and Technology) status seminar: Solar-assisted district heat supply - seasonal heat storage that took place in Neckarsulm on 19th and 20th May. 1998. The report contains the reference papers and the status reports of all projects supported under the Ministry`s SOLARTHERMIE programme that have already been finished or are still running. (orig.) [Deutsch] Der vorliegende Statusbericht wird anlaesslich des BMBF-Statusseminars: Solarunterstuetzte Nahwaermeversorgung - Saisonale Waermespeicherung am 19. und 20. Mai 1998 in Neckarsulm herausgegeben. Der Bericht enthaelt neben den Tagungsbeitraegen auch die Sachstandsberichte aller Projekte, die zu diesem Thema in den letzten Jahren von BMBF in dem Programm SOLARTHERMIE-2000 bereits abgeschlossen wurden oder z.Zt. gefoerdert werden. (orig.)

  1. Quercetin and isorhamnetin in sweet and red cultivars of onion (Allium cepa L.) at harvest, after field curing, heat treatment, and storage.

    Science.gov (United States)

    Olsson, Marie E; Gustavsson, Karl-Erik; Vågen, Ingunn M

    2010-02-24

    Effects of heat treatment and storage on quercetin and isorhamnetin content, major and minor components of isorhamnetin, and quercetin glucosides and aglycone, were investigated in onion (Allium cepa L.). The sweet onion 'Recorra' and red onions 'Hyred' and 'Red Baron' were cultivated in the south part of Norway and thereafter stored for eight months. The onions were either not field dried, but stored directly, or field dried and then stored, or field dried and then heat treated before storage. Neither storage nor heat treatment caused any major differences in total flavonol content in the investigated sweet onion as well as in the red onion cultivars. The two major quercetin glucosides differed in their changes in content during storage; quercetin-4'-glucoside did not show any consistent changes during storage in the two red cultivars, independent of treatment, whereas quercetin-3,4'-diglucoside increased significantly by 30 or 51%, respectively, during storage in 'Hyred' and 'Red Baron' in the 24 h heat treated onions. Isorhamnetin-4'-glucoside, which might possibly be of special interest from a human health point of view, was present at 2-3 times higher amount in the sweet onion cultivar than in the two red cultivars. Some of the quercetin glucosides present at lower concentrations, isorhamnetin-3,4'-diglucoside, quercetin-3,7,4'-triglucoside, and quercetin-7,4'-diglucoside, increased during storage in all treatments in both 'Hyred' and 'Red Baron', though sometimes a decrease was found at the end of storage.

  2. Annual Collection and Storage of Solar Energy for the Heating of Buildings, Report No. 3. Semi-Annual Progress Report, August 1977 - January 1978.

    Science.gov (United States)

    Beard, J. Taylor; And Others

    This report is part of a series from the Department of Energy on the use of solar energy in heating buildings. Described here is a new system for year around collection and storage of solar energy. This system has been operated at the University of Virginia for over a year. Composed of an underground hot water storage system and solar collection,…

  3. Quality of cut lettuce treated by heat shock: prevention of enzymatic browning, repression of phenylalanine ammonia-lyase activity, and improvement on sensory evaluation during storage.

    Science.gov (United States)

    Murata, Masatsune; Tanaka, Eriko; Minoura, Emiko; Homma, Seiichi

    2004-03-01

    Stored cut lettuce gradually turns brown on the cut section after several days of storage, because cutting induces phenylalanine ammonia-lyase (PAL) activity, the biosynthesis of polyphenol is promoted, and the polyphenols are oxidized by polyphenol oxidase. Here, the effect of heat shock treatment at 50 degrees C for 90 s on the quality of cut lettuce during cold storage was examined. The heat shock treatment significantly repressed the induction of PAL activity and phenolics accumulation in cut lettuce during storage, and prevented the browning of cut lettuce. Ascorbic acid content was not affected by the heat shock treatment. The sensory analysis showed that the organoleptic quality of cut lettuce treated by heat shock was significantly better than that of the control cut lettuce. These results show that heat shock treatment is useful for prolonging the shelf life of cut lettuce.

  4. CFD Analysis on the Passive Heat Removal by Helium and Air in the Canister of Spent Fuel Dry Storage System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Do Young; Jeong, Ui Ju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

    2016-05-15

    In the current commercial design, the canister of the dry storage system is mainly backfilled with helium gas. Helium gas shows very conductive behavior due to high thermal conductivity and small density change with temperature. However, other gases such as air, argon, or nitrogen are expected to show effective convective behavior. Thus these are also considered as candidates for the backfill gas to provide effective coolability. In this study, to compare the dominant cooling mechanism and effectiveness of cooling between helium gas and air, a computational fluid dynamics (CFD) analysis for the canister of spent fuel dry storage system with backfill gas of helium and air is carried out. In this study, CFD simulations for the helium and air backfilled gas for dry storage system canister were carried out using ANSYS FLUENT code. For the comparison work, two backfilled fluids were modeled with same initial and boundary conditions. The observed major difference can be summarized as follows. - The simulation results showed the difference in dominant heat removal mechanism. Conduction for helium, and convection for air considering Reynolds number distribution. - The temperature gradient inside the fuel assembly showed that in case of air, more effective heat mixing occurred compared to helium.

  5. Saisonal heat storage in mine caverns. Concepts and technical solutions. Second technical report. Saisonal heat storage of solar low temperature heat in mines. Solar mining; Saisonale Waermespeicherung in Grubenraeumen. Konzepte und technische Loesungen. 2. Technischer Fachbericht. Saisonale Speicherung solarer Niedertemperaturwaerme in Bergwerken. Solarenergiebergbau

    Energy Technology Data Exchange (ETDEWEB)

    Eikmeier, B.; Mohr, M.; Unger, H.

    1999-03-01

    The Second Technical Report of the project `Saisonal Storage of Solar Low Temperature Heat in Mines` describes different concepts to realize seasonal storage in mines and suitable district heat systems. The different storage designs and concepts are presented and evaluated in detail. The fundamental differences between the use of a tunnel or a shaft are discussed as well as the storage filling with a fluid or a mineral material. Technical solutions for the integration of a seasonal storage in mines are examined. Different solutions for storage sealing stand for choice. It is shown that the use of air-placed concrete represents a particularly suitable method due to the cost advantages and the flexible operation of the procedure compared with other seal systems. An exemplary system design leads to specific investment costs of 115 DM/m{sup 3} to 300 DM/m{sup 3} for the saisonal storage depending on the boundary conditions (tightness of the surrounding rock, use of available pipework etc.). The latter amount equals the height of the costs payed for the concrete underground tanks in Hamburg-Bramfeld and Friedrichshafen. It is shown that the costs for the use of mines for saisonal storage is comparable to those of existing systems at least; in favorable cases definitely lower costs may be achievable. In any case, a specific evaluation, taking account of local boundary conditions and circumstances, is necessay. On the basis of the boundary conditions below and the situation above ground, many locations in the Ruhr area were estimated concerning their suitability for this project. Favorable locations could be found within almost all coal industry areas. The plan for house buildings at these locations is suitable for the application of a district heat network. Although the examination of seasonal heat storage in mines is not concluded up to now, the presently achieved information indicates very positive results in all sections (i.e. investment costs, technical feasibility

  6. Potential of an adsorbent coated aluminum sponge asa heat storage and coldness storage; Potenzial von Adsorbens-beschichtetem Aluminiumschwamm als Waerme- und Kaeltespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Demmer, Thomas; Heyse, Joerg [Robert Bosch GmbH, Stuttgart (Germany); Mueller, Dirk [RWTH Aachen (Germany). E.ON Energy Research Center

    2012-07-01

    In the case of electric-powered vehicles, it cannot be waived on the conditioning of the passenger compartment can not be waived in electric cars. However, if electric power from the battery is used for the supply of thermal energy, than driving energy is cannibalized. For mass-produced electric-powered vehicles, the halving of the already limited striking distance due to the electric heater in the winter could be detected in real operation. Thus, a concept for a battery-independent and thus distance-optimal conditioning of electric-powered vehicles is examined based on a thermal adsorption storage for cooling and heating. In order to realize an implementation of a closed adsorption system in a vehicle, it is necessary to optimize the energy density and power density as well as to match the needs. A new composite material is considered for the construction of the adsorber heat exchanger. It is open-pore aluminum sponge which is manufactured inexpensively by means of a pressure casting method. A microporous adsorbent is synthesized on the inner surface of using an adsorbent volume of 40 %. A high volumetric energy density can be closed. Since the aluminum sponge can be cast in heat exchanger structures, a high power density is also achieved with this adsorber concept. The design and optimization of adsorbent heat exchangers which are built up on the composite material mentioned above is described by means of numerical simulation. The simulation models used were validated with laboratory tests on samples of the composite material.

  7. Ser2 from Serratia liquefaciens L53: A new heat stable protease able to destabilize UHT milk during its storage.

    Science.gov (United States)

    Baglinière, François; Tanguy, Gaëlle; Salgado, Rafael Locatelli; Jardin, Julien; Rousseau, Florence; Robert, Benoît; Harel-Oger, Marielle; Vanetti, Maria Cristina Dantas; Gaucheron, Frédéric

    2017-08-15

    The heat-stable protease Ser2 is secreted by the species Serratia liquefaciens, a psychrotrophic bacteria frequently found in raw milk. To understand the physicochemical modifications of casein micelles induced by Ser2 and to confirm its implication in UHT milk destabilization, the enzyme was purified and added to microfiltered raw milk before UHT treatment. UHT milk destabilization was investigated during 90days of storage. A visual destabilization appeared after 8days of storage with the presence of sediment. Zeta potential increase and formation of aggregates were observed during the storage. Using tandem mass spectrometry, numerous released peptides from the four caseins were identified at the end of storage. Caseins were hydrolyzed in the preferential order β->α s1 ->κ->α s2 . No specific peptidic hydrolysed bond was detected. The present study confirmed that the presence of the protease Ser2 in raw milk can be one of the main causes of UHT milk destabilization. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Energy storage and grid for electricity, gas, fuel and heat. A system-wide approach

    Energy Technology Data Exchange (ETDEWEB)

    Benesch, Wolfgang A. [STEAG Energy Services GmbH, Essen (Germany); Kakaras, Emmanouil [Mitsubishi Hitachi Power Systems Europe GmbH, Duisburg (Germany)

    2016-07-01

    Renewable energies are asked for more and more worldwide. Even though they cannot generate electricity 8760 h/a year. This can be accomplished by flexible conventional power stations as well as storage systems. Especially the storage systems have to be developed technical wise and especially economic wise. An example of an integrated approach is the methanol production with a coal fired power plant. An overview showing the technical features as well as the strategic opportunities of such kind of approach is given.

  9. Solar heating system for warming and hot water preparation by short term storage

    Energy Technology Data Exchange (ETDEWEB)

    Isakson, P.; Lagerkvist, K.O.; Kjaerboe, P.; Kristensen, P.O.

    1984-01-01

    The state of the art concerning solar heating of houses is described and the future possibilities are discussed. The experience shows that heat losses of the existing systems were large. On the other hand it is possible to substitute one third of purchased energy by solar energy. The conservation potential of residential buildings is calculated to be 4 TWh. The cost is however double as high as the cost of electric heating. The performance of a combined solar heating system has been calculated by computerized simulation. The results point out the future potential.

  10. Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

    DEFF Research Database (Denmark)

    Dannemand, Mark; Johansen, Jakob Berg; Kong, Weiqiang

    2016-01-01

    unit was tested with 116.3 kg SAT with 0.5% Xanthan rubber as a thickening agent and 4.4% graphite powder. The heat exchange capacity rate during charge was significantly lower for the unit with SAT and Xanthan rubber compared to the unit with SAT and extra water. This was due to less convection...... in the thickened phase change material after melting. The heat content in the fully charged state and the heat released after solidification of the supercooled SAT mixtures at ambient temperature was higher for the unit with the thickened SAT mixture. The heat discharged after solidification of the supercooled SAT...

  11. The options for heat and cold storage. Unjust fear fro drilling; WKO biedt kansen. Angst voor boringen vaak onterecht

    Energy Technology Data Exchange (ETDEWEB)

    Van Beek, H.

    2009-06-15

    Heat and cold storage can offer many opportunities for sustainable energy solutions. Still, authorities and clients often fear ground drillings. The fear of breaking pipes, unclear legislation and bad drillings plays an important role. Usually, this fear is unjust, though. (mk) [Dutch] Warmte-koudeopslag (WKO) kan veel mogelijkheden bieden voor duurzame energieoplossingen. Toch zijn overheden en opdrachtgevers vaak huiverig voor grondboringen. De angst voor leidingen die kapot gaan, onduidelijke wetgeving en slechte boringen speelt hierbij een belangrijke rol. Deze angst is echter meestal onterecht.

  12. Laboratory Testing of Solar Combi System with Compact Long Term PCM Heat Storage

    DEFF Research Database (Denmark)

    Johansen, Jakob Berg; Englmair, Gerald; Dannemand, Mark

    2016-01-01

    ) can provide a more compact way of storing heat. Sodium acetate trihydrate (SAT) is a good candidate material as it has a relatively high heat of fusion and in addition it has the ability to supercool to room temperature without solidifying. In this paper results from the test of a solar combi system...

  13. Environmental assessment for the relocation and storage of isotopic heat sources, Hanford Site, Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    As part of a bilateral agreement between the Federal Minister for Research and Technology of the Federal Republic of Germany (FRG) and the DOE, Pacific Northwest National Laboratory (PNNL) developed processes for the treatment and immobilization of high-level radioactive waste. One element of this bilateral agreement was the production of sealed isotopic heat sources. During the mid-1980s, 30 sealed isotopic heat sources were manufactured. The sources contain a total of approximately 8.3 million curies consisting predominantly of cesium-137 and strontium-90 with trace amounts of transuranic contamination. Currently, the sources are stored in A-Cell of the 324 Building. Intense radiation fields from the sources are causing the cell windows and equipment to deteriorate. Originally, it was not intended to store the isotopic heat sources for this length of time in A-cell. The 34 isotopic heat sources are classified as remote handled transuranic wastes. Thirty-one of the isotopic heat sources are sealed, and seals on the three remaining isotopic heat sources have not been verified. However, a decision has been made to place the remaining three isotopic heat sources in the CASTOR cask(s). The Washington State Department of Health (WDOH) has concurred that isotopic heat sources with verified seals or those placed into CASTOR cask(s) can be considered sealed (no potential to emit radioactive air emissions) and are exempt from WAC Chapter 246-247, Radiation Protection-Air Emissions.

  14. Applications of thermal energy storage to process heat and waste heat recovery in the iron and steel industry

    Science.gov (United States)

    Katter, L. B.; Peterson, D. J.

    1978-01-01

    The system identified operates from the primary arc furnace evacuation system as a heat source. Energy from the fume stream is stored as sensible energy in a solid medium (packed bed). A steam-driven turbine is arranged to generate power for peak shaving. A parametric design approach is presented since the overall system design, at optimum payback is strongly dependent upon the nature of the electric pricing structure. The scope of the project was limited to consideration of available technology so that industry-wide application could be achieved by 1985. A search of the literature, coupled with interviews with representatives of major steel producers, served as the means whereby the techniques and technologies indicated for the specific site are extrapolated to the industry as a whole and to the 1985 time frame. The conclusion of the study is that by 1985, a national yearly savings of 1.9 million barrels of oil could be realized through recovery of waste heat from primary arc furnace fume gases on an industry-wide basis. Economic studies indicate that the proposed system has a plant payback time of approximately 5 years.

  15. Advanced latent heat of fusion thermal energy storage for solar power systems

    Science.gov (United States)

    Phillips, W. M.; Stearns, J. W.

    1985-01-01

    The use of solar thermal power systems coupled with thermal energy storage (TES) is being studied for both terrestrial and space applications. In the case of terrestrial applications, it was found that one or two hours of TES could shift the insolation peak (solar noon) to coincide with user peak loads. The use of a phase change material (PCM) is attractive because of the higher energy storage density which can be achieved. However, the use of PCM has also certain disadvantages which must be addressed. Proof of concept testing was undertaken to evaluate corrosive effects and thermal ratcheting effects in a slurry system. It is concluded that the considered alkali metal/alkali salt slurry approach to TES appears to be very viable, taking into account an elimination of thermal ratcheting in storage systems and the reduction of corrosive effects. The approach appears to be useful for an employment involving temperatures applicable to Brayton or Stirling cycles.

  16. Facade element with integrated latent heat storage and sun shading; TWD-Fassadenelement mit integriertem Latentspeicher und Sonnenschutz

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, D.; Nussbaumer, T.

    2002-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of on-site measurements made on transparent insulating material (TIM) elements that have been used in a single-family home built to 'passive house' standards in Ebnat-Kappel in Switzerland as part of a pilot and demonstration project. The aims of the project and the various passive components of the panels are described. These are a paraffin-based storage layer that stores / releases latent heat of melting, a glass prism sheet that prevents summer sunshine entering the house and two further glass window panes with infrared reflecting layers. The functioning of the TIM system is looked at in detail. Data on the performance of the complete passive house system including typical energy-relevant temperature curves for ambient and room temperature, heat-recovery system and buried ducting for air pre-heating and cooling are also presented, as are curves for the energy consumption of the house's heat pump and domestic hot water preparation.

  17. Fuel-efficiency of hydrogen and heat storage technologies for integration of fluctuating renewable energy sources

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad; Lund, Henrik

    2005-01-01

    This paper presents the methodology and results of analysing the use of different energy storage technologies in the task of integration of fluctuating renewable energy sources (RES) into the electricity supply. The analysis is done on the complete electricity system including renewable energy so...

  18. Effect of processing by hydrostatic high pressure of two ready to heat vegetable meals and stability after refrigerated storage.

    Science.gov (United States)

    Masegosa, Rosa; Delgado-Adámez, Jonathan; Contador, Rebeca; Sánchez-Íñiguez, Francisco; Ramírez, Rosario

    2014-12-01

    The effect of high pressure processing (HPP) (400 and 600 MPa for 1 and 5 min) and the stability during storage were studied in two ready to heat vegetable meals: meal A, mainly composed by pumpkin and broccoli, and meal B, mainly composed by eggplant, zucchini, chard and spinach. The treatment at 600 MPa/5 min was the most effective to reduce the initial microbial loads of the meals and maintained better the microbial safety during storage. HPP had no effect on the physico-chemical and sensory properties. HPP at 600 MPa increased the antioxidant activity of the meal A. In contrast HPP reduced the antioxidant activity of the meal B, although in general high levels of antioxidants were maintained after processing and during storage. In conclusion, treatments at 600 MPa for 5 min were the most suitable to increase the shelf-life of the meals without affecting their physico-chemical, antioxidant and sensory properties. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  19. Cold and heat storage in downtown Berlin; Kaelte und Waermespeicherung im Zentrum Berlins

    Energy Technology Data Exchange (ETDEWEB)

    Seibt, P.; Brandt, W.; Kabus, F.; Moellmann, G.; Poppei, J. [Geothermie Neubrandenburg GmbH (Germany)

    1997-12-01

    The concept of energy supply for the seat of the German Parliament is based on self-sufficiency by using motor-driven district heating power stations. Esterified vegetable oil (bio-diesel) serves as fuel. These motor-driven power stations are operated depending on the amount of power required actually. The heat energy which is released when generating power at the temperature level >100 C - which is favourable for heating purposes - serves directly for heat supply or the driving a refrigerating machine/heat pump for the supply of cooling energy in summer and low-temperature heat in winter. As the demand on heat and power supply often will not be parallel, there will be a temporary surplus of heat offered by the motor-driven power station, and at other times it will be deficient. That is why surplus heat from the motor-driven power station is stored in a deep aquifer heat reservoir for recovery and utilisation for heating in winter. By using a geothermal saline water reservoir, the waste heat from the motor-driven power station can be fed into it at a temperature level ranging from 60.. 80 C and recovered and utilised at a temperature level ranging from 60.. 20 C. A shallow groundwater aquifer cold storing reservoir serves for cooling: the cold stored in winter is supplied in summer to the cooling equipment of the building by direct cooling with the cold water form the aquifer (heat exchange) at a temperature level of 14/15 C. The cooling demand in case of air dehumidification at a temperature level of 6/12 C is covered by a cooling machine which is also cooled with the cold water from the aquifer. As cooling machine/heat pump an environment-friendly, CFC-free absorption machine is used working on a combination of water and lithium bromide. The machine is driven by the waste heat from the motor-driven power plant. (orig.) [Deutsch] Im Zentrum des Systems der Energieversorgung der Parlamentsbauten steht die autarke Energiebereitstellung durch den Einsatz von

  20. The effect of delay between heat treatment and cold storage on alleviation of chilling injury in banana fruit.

    Science.gov (United States)

    Wang, Haibo; Zhang, Zhaoqi; Xu, Lanying; Huang, Xuemei; Pang, Xuequn

    2012-10-01

    To understand the mechanisms leading to the enhanced chilling resistance of banana by hot-water dipping (HWD, 52 °C for 3 min), we investigated the effect of a 0.5-24 h delay between HWD and cold storage on chilling resistance and the change related to the metabolism of reactive oxygen species (ROS). The HWD-treated fruit with a delay of less than 6 h exhibited markedly less chilling injury than the non-heated control fruit, while a delay more than 6 h resulted in significant loss in chilling resistance. Increased hydrogen peroxide content and rate of superoxide radical production were detected in the fruit at 0.5-1.5 h after HWD treatment, and the levels declined with a longer delay, which may be correlated with the enhanced gene expression levels of the gene coding for a ROS-generating related enzyme, NADPH oxidase (MaNOX). Enhanced activities and gene expression of an ascorbate peroxidase (MaAPX) were recorded in the fruit at 1.5-6 h after the treatment, and after 6 h the ascorbate peroxidase levels decayed to the levels as the control fruit. The higher APX gene expression was maintained in the treated fruit with a 3 h delay during the subsequent cold storage at 7 °C, correlating with the enhanced chilling resistance. The HWD-treated fruit left at ambient temperature up to 6 h prior to cold storage maintained the effect of heat treatment and transiently increased ROS content, and the ascorbate peroxidase activity that occurred 0.5-6 h after the treatment may be correlated with the elevated chilling resistance induced by HWD treatment. Copyright © 2012 Society of Chemical Industry.

  1. Increasing heat storage by wearing extra clothing during upper body exercise up-regulates heat shock protein 70 but does not modify the cytokine response.

    Science.gov (United States)

    Leicht, Christof A; Papanagopoulos, Aris; Haghighat, Sam; Faulkner, Steve H

    2017-09-01

    Plasma heat shock protein 70 (HSP70) concentrations rise during heat stress, which can independently induce cytokine production. Upper body exercise normally results in modest body temperature elevations. The aim of this study was to investigate the impacts of additional clothing on the body temperature, cytokine and HSP70 responses during this exercise modality. Thirteen males performed 45-min constant-load arm cranking at 63% maximum aerobic power (62 ± 7%V̇O2peak) in either a non-permeable whole-body suit (intervention, INT) or shorts and T-shirt (control, CON). Exercise resulted in a significant increase of IL-6 and IL-1ra plasma concentrations (P  0.19). The increase in HSP70 from pre to post was only significant for INT (0.12 ± 0.11ng∙mL-1, P < 0.01 vs. 0.04 ± 0.18 ng∙mL-1, P = 0.77). Immediately following exercise, Tcore was elevated by 0.46 ± 0.29 (INT) and 0.37 ± 0.23ºC (CON), respectively (P < 0.01), with no difference between conditions (P = 0.16). The rise in mean Tskin (2.88 ± 0.50 and 0.30 ± 0.89ºC, respectively) and maximum heat storage (3.24 ± 1.08 and 1.20 ± 1.04 J∙g-1, respectively) was higher during INT (P < 0.01). Despite large differences in heat storage between conditions, the HSP70 elevations during INT, even though significant, were very modest. Possibly, the Tcore elevations were too low to induce a more pronounced HSP70 response to ultimately affect cytokine production.

  2. Worldwide clean energy system technology using hydrogen (WE-NET). subtask 5. Development of hydrogen transfer and storage technology (research and development of technologies for hydrogen transport and storage by hydrogen absorbing alloys); Suiso riyo kokusai clean energy system gijutsu (WE-NET). subtask 5. Suiso yuso chozo gijutsu no kaihatsu (bunsan yuso chozoyo suiso kyuzo gokin no kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This report describes a guiding principle of new hydrogen absorbing alloy design, case studies on the stationary hydrogen storage systems for multiple dwelling houses using hydrogen absorbing alloys and on the hydrogen fuel tank systems for a motor vehicle, and survey on development status in the world. As a result of the investigation of alloys, it was concluded that realization of hydrogen absorbing alloys with new target properties of the WE-NET Project is not easy through the current technology. It was found that two kinds of Mg-based and V-based high capacity materials must be selected as target alloys among current alloys, and that three techniques, i.e., ultra-fine microstructure, composite, and amorphousness, are effective for improving the hydrogen discharge property which has been a problem of these alloys. It was desired that the latest techniques are established by integrating these materials and techniques. It is necessary to promote the development of brake-through new materials by new concepts and technologies through the cooperation of national institutes, universities, and companies. 124 refs., 56 figs., 11 tabs.

  3. The electrohydraulic balance of the solar heat storage with autonomous power supply

    Directory of Open Access Journals (Sweden)

    M. K. Marahtanov

    2014-01-01

    Full Text Available The introduction of the paper emphasizes an increasingly important role of alternative power sources nowadays. At the same time, a solar collector (suntrap is one of the most frequent techniques to use the solar energy. It is an absorber that picks up solar radiation and heats a heat carrier circulating in the close loop. Then the heat is transferred to the heat accumulator that is integrated in the hot-tap water system (HWS.The paper presents a prospective circuit of the solar collector. It differs from the traditional one because, in addition to absorbing panel, it uses photoconverters to generate electric power for the circulating pump. The advantage of this system is that for operation such a solar energy converter has no need in external power sources, i.e. it is autonomous. The need to calculate the essential thermo-physical parameters that ensure no-break system operation was stated as a main objective of the work.The suggested circuit has a photocell panel to convert solar radiation into dc voltage of 12 V. In case of a lack of the solar energy an accumulator battery can be used for feeding. To ensure the no-break supply of power an adaptor is offered.To calculate a density distribution of solar radiation a sine law is offered depending on the time of day and geographical locality. This dependence was used to obtain the expressions for calculating the water temperature in boiler over daytime.Further, the calculations have been done for the operating conditions under which an efficient heat exchange will be provided with the minimum consumption of electric power for the heat carrier circulation in the first loop. For this purpose, a pump power was calculated depending on consumption and hydraulic losses of head in the pipeline. As a minimum required consumption the value has been chosen at which a laminar flow regime changes to the turbulent one because of the most efficient heat exchange being both in collector and in heat accumulator

  4. Analysis of the Storage Capacity in an Aggregated Heat Pump Portfolio

    DEFF Research Database (Denmark)

    Nielsen, Kirsten Mølgaard; Andersen, Palle; Pedersen, Tom Søndergård

    2015-01-01

    to suitable time slots and this makes it possible to avoid some grid storage capacity. The energy is bought based on prediction of energy prices, weather forecast and an aggregated house model on the NORD POOL day-ahead market. The bought energy is then distributed to the houses using a model free sorting...... (scheduling) algorithm. The properties of this scheduling are investigated in the paper especially the flexibility and ability to trade on the intra-day regulating market is in focus....

  5. Influence of storage, heat treatment, and solids composition on the bleaching of whey with hydrogen peroxide.

    Science.gov (United States)

    Li, Xiaomeng E; Campbell, Rachel E; Fox, Aaron J; Gerard, Patrick D; Drake, MaryAnne

    2012-07-01

    The residual annatto colorant in liquid whey is bleached to provide a desired neutral color in dried whey ingredients. This study evaluated the influence of starter culture, whey solids and composition, and spray drying on bleaching efficacy. Cheddar cheese whey with annatto was manufactured with starter culture or by addition of lactic acid and rennet. Pasteurized fat-separated whey was ultrafiltered (retentate) and spray dried to 34% whey protein concentrate (WPC34). Aliquots were bleached at 60 °C for 1 h (hydrogen peroxide, 250 ppm), before pasteurization, after pasteurization, after storage at 3 °C and after freezing at -20 °C. Aliquots of retentate were bleached analogously immediately and after storage at 3 or -20 °C. Freshly spray dried WPC34 was rehydrated to 9% (w/w) solids and bleached. In a final experiment, pasteurized fat-separated whey was ultrafiltered and spray dried to WPC34 and WPC80. The WPC34 and WPC80 retentates were diluted to 7 or 9% solids (w/w) and bleached at 50 °C for 1 h. Freshly spray-dried WPC34 and WPC80 were rehydrated to 9 or 12% solids and bleached. Bleaching efficacy was measured by extraction and quantification of norbixin. Each experiment was replicated 3 times. Starter culture, fat separation, or pasteurization did not impact bleaching efficacy (P > 0.05) while cold or frozen storage decreased bleaching efficacy (P whey or 34% (w/w) protein liquid retentate (P whey. Optimization of whey bleaching conditions is important to reduce the negative effects of bleaching on the flavor of dried whey ingredients. This study established that liquid storage and whey composition are critical processing points that influence bleaching efficacy. © 2012 Institute of Food Technologists®

  6. Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Xun Yang

    2017-08-01

    Full Text Available In this study, the dynamic melting process of the phase change material (PCM in a vertical cylindrical tube-in-tank thermal energy storage (TES unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF. A numerical model using the computational fluid dynamics (CFD approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

  7. Heat stress in pigs is accompanied by adipose tissue-specific responses that favor increased triglyceride storage.

    Science.gov (United States)

    Qu, H; Yan, H; Lu, H; Donkin, S S; Ajuwon, K M

    2016-05-01

    Heat stress (HS) negatively affects all aspects of performance in pigs. Although certain tissue-specific responses in the liver, skeletal muscle, and intestine are known, there is paucity of information on responses within the adipose tissue. Therefore, the objective of this study was to delineate adipose tissue responses during HS in pigs. Thirty crossbred (Ossabaw × Duroc × Landrace) pigs were assigned to 3 treatments for 7 d. Treatments were 1) control and libitum fed (CON) with room temperature set at 20°C ± 1°C, 2) pair fed (PF) with room temperature as the CON treatment but pair fed to HS pigs, and 3) HS with room temperature 35°C ± 1°C and ad libitum access to feed. Compared with CON pigs, HS pigs had decreased feed intake and elevated skin temperature and respiration rate ( Heat stress also caused increased heat shock protein 70 (HSP70; = 0.067) and CCAT/enhancer-binding homologous protein (CHOP) content ( < 0.05) in the mesenteric fat compared with the CON treatment. In conclusion, induction of PCK1 expression in adipose tissue by HS suggests elevated glyceroneogenesis might be involved in the increased fat storage in pigs under HS.

  8. Effect of heat processing and storage time on migration of bisphenol A (BPA) and bisphenol A-diglycidyl ether (BADGE) to aqueous food simulant from Mexican can coatings.

    Science.gov (United States)

    Munguia-Lopez, E M; Soto-Valdez, H

    2001-08-01

    Effects of heat processing and storage time (up to 70 days) on migration of bisphenol A (BPA) and bisphenol A-diglycidyl ether (BADGE) from can coatings into an aqueous food simulant were determined. Distilled water was canned in two types of Mexican cans: for tuna and for jalapeño peppers. Results showed that there is an effect of heat treatment on migration of both compounds. Storage time did not show any effect in BPA migration from tuna cans. There was an effect of storage time on BPA migration from jalapeño pepper cans. Results for BADGE migration were affected by its susceptibility to hydrolyze in aqueous simulants. BADGE concentration decreased, or was not detected, during storage in both types of cans. Migration levels for BPA and BADGE were within 0.6-83.4 and Mercosur legislation limits. Other migrating compounds were detected, although no identification was performed.

  9. Solar heating system with seasonal storage for the 'Heumatt' housing development in Zurich; Solare Waermeversorgung mit saisonalem Speicher fuer die Wohnsiedlung Heumatt, Zuerich Seebach

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, P.; Juzi, H.

    2003-07-01

    This final report for the Swiss Federal Office of Energy describes a project proposal for the seasonal storage of heat produced by solar collectors to provide a fifty-percent coverage of the space heating and hot water demands of a housing scheme with 140 dwellings in Zurich, Switzerland. The report describes the project, including the collection of solar energy and the storage of heat in an underground storage area. Figures are given on the estimates of energy requirements and energy production. The investments needed for the realisation of the project are quoted. The report also includes a detailed report on the concept and reviews of the project made by the University of Applied Technology in Winterthur and that of Southern Switzerland.

  10. A modular approach to inverse modelling of a district heating facility with seasonal thermal energy storage

    DEFF Research Database (Denmark)

    Tordrup, Karl Woldum; Poulsen, Uffe Vestergaard; Nielsen, Carsten

    2017-01-01

    We use a modular approach to develop a TRNSYS model for a district heating facility by applying inverse modelling to one year of operational data for individual components. We assemble the components into a single TRNSYS model for the full system using the accumulation tanks as a central hub conn...

  11. Large solar heating system with seasonal storage for buld drying in Lisse, the Netherlands

    NARCIS (Netherlands)

    Bokhoven, T.P.; Geus, A.C. de

    1996-01-01

    Within IEA Task 14 (Advanced Solar Systems) of the IEA Solar Heating and Cooling Programme a working group was established dealing with large advanced solar energy systems (the Large Systems Working group). The goal of this working group was to generate a common base of experiences for the design

  12. Thermal analysis on organic phase change materials for heat storage applications

    Science.gov (United States)

    Lager, Daniel

    2016-07-01

    In this paper, methodologies based on thermal analysis to evaluate specific heat capacity, phase transition enthalpies, thermal cycling stability and thermal conductivity of organic phase change materials (PCMs) are discussed. Calibration routines for a disc type heat flow differential scanning calorimetry (hf-DSC) are compared and the applied heating rates are adapted due to the low thermal conductivity of the organic PCMs. An assessment of thermal conductivity measurements based on "Laser Flash Analysis" (LFA) and the "Transient Hot Bridge" method (THB) in solid and liquid state has been performed. It could be shown that a disc type hf-DSC is a useful method for measuring specific heat capacity, melting enthalpies and cycling stability of organic PCM if temperature and sensitivity calibration are adapted to the material and quantity to be measured. The LFA method shows repeatable and reproducible thermal diffusivity results in solid state and a high effort for sample preparation in comparison to THB in liquid state. Thermal conductivity results of the two applied methods show large deviations in liquid phase and have to be validated by further experiments.

  13. Efficiency gains of photovoltaic system using latent heat thermal energy storage

    NARCIS (Netherlands)

    Tan, Lippong; Date, Abhijit; Fernandes, Gabriel; Singh, Baljit; Ganguly, Sayantan

    This paper presents experimental assessments of the thermal and electrical performance of photovoltaic (PV) system by comparing the latent heat-cooled PV panel with the naturally-cooled equivalent. It is commonly known that the energy conversion efficiency of the PV cells declines with the increment

  14. Using the Synergy Between GERB/SEVIRI and Micrometeorological Data to Study the Relationship Between Surface Net Radiation and Soil Heat Flux at Local and Regional Scales

    Science.gov (United States)

    Ferreira, A. G.; Velázquez Blázquez, A.; Soria, E.; Lopez-Baeza, E.

    2009-04-01

    The surface energy exchange between the land surface and the atmosphere can be described by the energy balance equation Rn - H - LE - G = 0, where Rn represents net radiation, H the sensible heat flux, LE, the latent heat flux and G the soil heat flux. In this work the relationship between Rn and G is studied over vineyard crops, a relative sparse vegetation cover crop where, according to the literature, it is expected that G consumes a significant proportion of Rn. In order to study this relationship at local and regional scales, micrometeorological observations and METEOSAT Second Generation (MSG) satellite data have been used. MSG through the GERB (Geostationary Earth Radiation Budget) and the SEVIRI (Spinning Enhanced Visible and Infrared Imager) sensors can provide estimates of net radiation and required land surface temperature (LST) information with a frequency of 15 min intervals. The necessary micrometeorological parameters, to compare with satellite data, were collected during the full vine growing season of 2007 (May to September) in a field experiment carried out at the Valencia Anchor Station (VAS) site area. The VAS is a robust reference meteorological station which is successfully used preferentially for validation of low spatial resolution satellite data and products. It is located on the natural region of the Utiel-Requena Plateau, at about 80 km west from the city of Valencia, Spain, and represents a reasonable homogeneous area of about 50 km x 50 km dedicated primarily to growing vines. The methodology utilized to study the relationship between Rn and G at local and regional scales, was that proposed by Santanello and Friedel (2002), where surface temperature can be obtained from SEVIRI that provides estimates of LST with unprecedented frequency of 15 min intervals with a spatial resolution of 3.1 km, thus totally covering its diurnal course. The preliminary results show that: 1- the correlation between the ground measurements and SEVIRI LST is

  15. Studies of natural convection heat transfer in dry spent fuel storage casks using the cobra-SFS thermal-hydraulic computer code

    Energy Technology Data Exchange (ETDEWEB)

    Michener, T. [Pacific Northwest National Laboratory, Richland WA (United States); Guttmann, J.; Bajwa, C. [United States Nuclear Regulatory Commission, One White Flin North, Rockville MD (United States)

    2001-07-01

    The purpose of this study is to identify the importance of natural convection cooling within a nuclear dry spent fuel storage system. In the past, applicants submitting requests to the United States Nuclear Regulatory Commission (USNRC) for a license for a dry spent fuel storage system design did not rigorously treat natural convection within the fuel package of the dry storage system. Typically, the applicant applies heat transfer correlations that raise the thermal conductivity of the materials (gas and solid structures) to account for the impact of convection on the thermal performance of the system. (author)

  16. Performance Maintenance of Dye-Sensitized Solar Cells Using a Latent Heat Storage Material

    Science.gov (United States)

    Haruki, Naoto; Horibe, Akihiko

    2017-07-01

    Recently, there has been considerable interest in various renewable energies. Among them, solar cell production has increased markedly because the photovoltaic is a clean and safe power generation method. The dye-sensitized solar cell (DSSC) has attracted much attention as an alternative to silicon solar cells due to lower manufacturing costs and plentiful resources for DSSC production. However, the performance of DSSCs has been limited by their durability and low photoelectric conversion efficiency. Temperature control of DSSCs via phase-change materials (PCMs) is expected to improve performance. In this study, DSSCs were heated or cooled with a heat exchanger copper block that was in contact with a PCM (heptadecane), while being irradiated by a solar simulator light source. The durability and photoelectric conversion efficiency of the DSSC improved under PCM temperature control.

  17. Underground storage system of solar energy for the year round heating

    Energy Technology Data Exchange (ETDEWEB)

    Schurchkov, A.; Belyaeva, T.; Gorokhov, M. [Institute of Engineering Thermophysics, National Academy of Sciences, Kiev (Ukraine)

    1997-12-31

    This presentation describes a pilot solar heat supply installation in an apartment building in Yalta, Ukraine. Energy conservation problems and introduction of non-traditional and resumed power sources into manufacture practice are the most actual problems for scientists and engineers of Ukraine, which experiences, at present, a terrible shortage of energy carriers. Scientific-research developments of Ukrainian experts, as well as foreigners` experiences indicate an absolute expediency of introduction of energy conservation technologies. At the same time the scientific-technical potential and the industrial basis in Ukraine make favourable conditions to realize successfully energy conservation measures. One of perspective ways of power resource saving is to smooth in time schedules of heat manufacture and consumption by using various kinds of systems - a seasonal, as well as a short-term accumulation system

  18. Influence of Prolonged Storage Process, Pasteurization, and Heat Treatment on Biologically-active Human Milk Proteins

    Directory of Open Access Journals (Sweden)

    Jih-Chin Chang

    2013-12-01

    Conclusion: Various freezing/heating/pasteurization processes applied to human milk prior to delivery to neonates could affect the concentration of immunomodulatory proteins, especially lactoferrin, secretory immunoglobulin A, and lysozyme. Leptin was unaffected by the various handling processes tested. Fresh milk was found to be the best food for neonates. Further studies are warranted to evaluate the functional activity of these proteins and their effects on infants' immunological status.

  19. Development of heat exchanger for high temperature energy storage with bulk materials

    Science.gov (United States)

    Boura, Cristiano Teixeira; Niederwestberg, Stefan; McLeod, Jacqueline; Herrmann, Ulf; Hoffschmidt, Bernhard

    2016-05-01

    This paper gives a general overview of the concept of a high temperature gas-to-particle heat exchanger, the corresponding test facilities and the results of laboratory tests. A description of the optimal bulk material and separator properties and their influences on the operating conditions is also given. The three phenomena pinning, blistering and blocking could be observed during the tests and were analysed in more detail using simulation software.

  20. High Temperature Latent Heat Thermal Energy Storage to Augment Solar Thermal Propulsion for Microsatellites

    Science.gov (United States)

    2015-08-30

    heat of fusion . In this work, boron is considered a long-term high performance solution and silicon is presented as a near term development target with... conceptual studies. However, there have been no thorough investigations due to the absence of existing research in addition to cost and schedule constraints...driven by a nuclear thermal energy source. Zubrin et al. proposed a “bi-modal” approach which modified an existing 40 kWe nuclear-thermionic reactor

  1. A Comparison of the Box Type Two Solar Cookers with Latent Heat Storage

    Directory of Open Access Journals (Sweden)

    Numan YÜKSEL

    2013-04-01

    Full Text Available In this study, the use potential of solar cookers storing by latent heat technical of solar energy was experimentally researched and these cookers were compared. For this purpose, the temperatures of the cookers’ phase change material (PCM were continuously measured during the day, both during sun and after sunset, by filling with the phase change material around the solar cooker manufactured. From the measurements, while the temperature of the PCM in the big cooker filled the large amount of PCM is 92,8 °C, the temperature of the PCM in the other cooker is 80,4 °C.However, the better performance is reached by the cooker-1 in which the maximum surface temperature during the day is 111 °C and the heat is preserved to 52 °C until the next morning. Also, the surface temperature in the cooker is reached to the temperature of 85 °C at the end of 1 hour. It is obtained that the utilization rate or efficiency of the solar cooker-1 is % 36,89 and that of the other cooker is %30,10. It is seen that the solar cookers should be designed for the purpose, depending on the amount of PCM and the cooker’s size. It is concluded that the solar cooker designed can be effectively used with the different purposes, such as heating-cooking, on 24 hours a day, an important part of the year without the need for the other heat source

  2. Laboratory Test of a Cylindrical Heat Storage Module with Water and Sodium Acetate Trihydrate

    DEFF Research Database (Denmark)

    Dannemand, Mark; Kong, Weiqiang; Johansen, Jakob Berg

    2016-01-01

    phase change material was reduced over 17 test cycles. The heat released after solidification of the supercooled sodium acetate trihydrate with thickening agent and graphite was stable over the test cycles. Stable supercooling was obtained in 7 out of 17 test cycles with the module with sodium acetate...... trihydrate with extra water and in 6 out of 35 test cycles for the module with thickening agent....

  3. Experimental investigations on prototype heat storage units utilizing stable supercooling of sodium acetate trihydrate mixtures

    DEFF Research Database (Denmark)

    Dannemand, Mark; Dragsted, Janne; Fan, Jianhua

    2016-01-01

    was filled with 220 kg SAT mixture thickened with 1% carboxymethyl cellulose. The heat exchange capacity rate during the charging of the unit with the extra water was significantly higher than for the unit with the thickening agent due to the different levels of convection. The SAT mixtures in the units were...... from the unit with SAT and the thickening agent after solidification was stable at 205 kJ/kg over 6 test cycles....

  4. Temporary heat storage by using combined heat and power in supplementary lighted greenhouses Proceedings of the Third International Symposium on Artificial Lighting in Horticulture

    NARCIS (Netherlands)

    Huijs, J.P.G.

    1997-01-01

    Because of better utilization possibilities of the produced heat, decentrally located combined heat and power installations achieve a higher energetic efficiency than producing heat and power separately. However, efficiency depends considerably on synchronism of heat and electricity demand. Using a

  5. Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage

    Science.gov (United States)

    Chieruzzi, Manila; Cerritelli, Gian F.; Miliozzi, Adio; Kenny, José M.

    2013-10-01

    In this study, different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (selected as phase change material) with nanoparticles using the direct-synthesis method. The thermal properties of the nanofluids obtained were investigated. These nanofluids can be used in concentrating solar plants with a reduction of storage material if an improvement in the specific heat is achieved. The base salt mixture was a NaNO3-KNO3 (60:40 ratio) binary salt. The nanoparticles used were silica (SiO2), alumina (Al2O3), titania (TiO2), and a mix of silica-alumina (SiO2-Al2O3). Three weight fractions were evaluated: 0.5, 1.0, and 1.5 wt.%. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements on thermophysical properties were performed by differential scanning calorimetry analysis and the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM). The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of 15% to 57% in the solid phase and of 1% to 22% in the liquid phase. In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt. These results deviated from the predictions of the theoretical model used. SEM suggests a greater interaction between these nanoparticles and the salt.

  6. Solid state phase change materials for thermal energy storage in passive solar heated buildings

    Science.gov (United States)

    Benson, D. K.; Christensen, C.

    1983-11-01

    A set of solid state phase change materials was evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol, pentaglycerine and neopentyl glycol. Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature within the range from less than 25 deg to 188 deg. Thermophysical properties such as thermal conductivity, density and volumetric expansion were measured. Computer simulations were used to predict the performance of various Trombe wall designs incorporating solid state phase change materials. Optimum performance was found to be sensitive to the choice of phase change temperatures and to the thermal conductivity of the phase change material. A molecular mechanism of the solid state phase transition is proposed and supported by infrared spectroscopic evidence.

  7. Finned double-tube PCM system as a waste heat storage

    Science.gov (United States)

    Alhamdo, M. H.; Theeb, M. A.; Golam, A. S.

    2015-11-01

    In this work, focus is taken on developing a waste heat recovery system for capturing potential of exhaust heat from an air conditioner unit to be reused later. This system has the ability to store heat in phase change material (PCM) and then release it to a discharge water system when required. To achieve this goal, a system of Finned, Water-PCM, Double tube (FWD) has been developed and tested. Different profiles of fins attached to the (FWD) system have been investigated for increasing the thermal conductivity of the PCM. These include using Circular Finned, Water-PCM, Double tube (CFWD) system; Longitudinal Finned, Water-PCM, Double tube (LFWD) system; Spiral Finned, Water-PCM, Double tube (SFWD) system; as well as; Without Fins, Water-PCM, Double tube (WFWD) system. An experimental test rig that attached to an air-conditioner unit has been built to include 32- tubes of the FWD systems for both vertical and horizontal layouts during charging and water discharging processes. Results show a significant performance improvement when using spiral and circular fins during charging process at vertical position. However, longitudinal and without fins showed better performance in horizontal position. Overall, the developed SFWD system in vertical position has been found to exhibit the most effective type due to the fastest PCM melting and solidification. As compared to the WFWD system, the FWD systems have been found to increase the PCM temperature gain of about 15.3% for SFWD system; 8.2% for CFWD; and 4.3% for LFWD system.

  8. Swiss energy research programme on solar heat and storage for 2008-2011; Programme de recherche energetique. Chaleur solaire et stockage pour la periode 2008-2011

    Energy Technology Data Exchange (ETDEWEB)

    Hadorn, J.-C.

    2009-07-15

    This report published by the Swiss Federal Office of Energy (SFOE) takes a look at the research programme on solar heat and heat storage for the years 2008 - 2011. This document presents some aspects of the solar thermal market in 2007, summarizes the main solar thermal technologies for buildings and sketches the main topics of the 'Solar Heat and Heat Storage' research programme. Research and development issues looked at focus mainly on the heating and cooling of buildings. The research and development issues for solar thermal technologies during the period 2008-2011 include improved performance and durability of solar collectors and components, new coatings for solar collectors based on nano-materials as well as simplified and standardised systems for solar heating and cooling. Building Integration and integration in existing heating systems and long-term work with a focus on new materials for storing heat for use in residential buildings are discussed. Also, calculation methods and simulation tools are examined. Pilot and demonstration projects are reviewed.

  9. Influence of wind power, plug-in electric vehicles, and heat storages on power system investments

    DEFF Research Database (Denmark)

    Kiviluoma, Juha; Meibom, Peter

    2010-01-01

    Due to rising fuel costs, the substantial price for CO2 emissions and decreasing wind power costs, wind power might become the least expensive source of power for an increasing number of power systems. This poses the questions of how wind power might change optimal investments in other forms...... electric vehicles. The model runs in an hourly time scale in order to accommodate the impact of variable power production from wind power. Electric vehicles store electricity for later use and can thus serve to increase the flexibility of the power system. Flexibility can also be upgraded by using heat...

  10. Phase Change Characteristics of a Nanoemulsion as a Latent Heat Storage Material

    Science.gov (United States)

    Fumoto, Koji; Sato, Noriaki; Kawaji, Masahiro; Kawanami, Tsuyoshi; Inamura, Takao

    2014-10-01

    The primary objective of this study was to investigate the fundamental phase change characteristics of a nanoemulsion using differential scanning calorimetry (DSC). Tetradecane, which has a slightly higher melting point than water, was utilized as the phase change material for the nanoemulsion. The melting point of the nanoemulsion, the melting peak temperature, and latent heat were examined in detail. Regarding the fundamental phase change characteristics of the nanoemulsion, it was found that its phase change characteristics were strongly affected by the temperature-scanning rate of the DSC. Moreover, it was confirmed that the phase change behavior does not change with repeated solidification and melting.

  11. Use of latent heat storage to conserve energy during drying and its effect on drying kinetics of a food product

    Energy Technology Data Exchange (ETDEWEB)

    Devahastin, Sakamon; Pitaksuriyarat, Saovakhon [Department of Food Engineering, King Mongkut' s University of Technology Thonburi, 91 Pracha u-tid Road, Bangkok 10140 (Thailand)

    2006-10-15

    The present study aimed at investigating the feasibility of using a latent heat storage (LHS) with paraffin wax as a phase change material (PCM) to store excess solar energy and release it when the energy availability is inadequate or not available. First, attention was given on the heat transfer characteristics of the PCM during the charge and discharge periods of the LHS. The effects of inlet hot air temperature in the range of 70-90{sup o}C and inlet air velocities of 1 and 2ms{sup -1} on the charge time were determined, while during the discharge period only the effect of inlet ambient air velocity was considered. The effect of the use of LHS on the drying kinetics of sweet potato and the ability of the LHS to conserve energy during drying of sweet potato were also determined. It was found that the drying rate of sweet potato increased with a decrease of the inlet ambient air velocity. The amount of the energy extractable from the LHS was 1920 and 1386kJminkg{sup -1} and the energy savings was 40% and 34% when using an inlet ambient air velocity of 1 and 2ms{sup -1}, respectively. (author)

  12. Incremental heating of Bishop Tuff sanidine reveals preeruptive radiogenic Ar and rapid remobilization from cold storage

    Science.gov (United States)

    Andersen, Nathan L.; Jicha, Brian R.; Singer, Brad S.; Hildreth, Wes

    2017-11-01

    Accurate and precise ages of large silicic eruptions are critical to calibrating the geologic timescale and gauging the tempo of changes in climate, biologic evolution, and magmatic processes throughout Earth history. The conventional approach to dating these eruptive products using the 40Ar/39Ar method is to fuse dozens of individual feldspar crystals. However, dispersion of fusion dates is common and interpretation is complicated by increasingly precise data obtained via multicollector mass spectrometry. Incremental heating of 49 individual Bishop Tuff (BT) sanidine crystals produces 40Ar/39Ar dates with reduced dispersion, yet we find a 16-ky range of plateau dates that is not attributable to excess Ar. We interpret this dispersion to reflect cooling of the magma reservoir margins below ˜475 °C, accumulation of radiogenic Ar, and rapid preeruption remobilization. Accordingly, these data elucidate the recycling of subsolidus material into voluminous rhyolite magma reservoirs and the effect of preeruptive magmatic processes on the 40Ar/39Ar system. The youngest sanidine dates, likely the most representative of the BT eruption age, yield a weighted mean of 764.8 ± 0.3/0.6 ka (2σ analytical/full uncertainty) indicating eruption only ˜7 ky following the Matuyama‑Brunhes magnetic polarity reversal. Single-crystal incremental heating provides leverage with which to interpret complex populations of 40Ar/39Ar sanidine and U-Pb zircon dates and a substantially improved capability to resolve the timing and causal relationship of events in the geologic record.

  13. Techno-Economic Assessment of Heat Transfer Fluid Buffering for Thermal Energy Storage in the Solar Field of Parabolic Trough Solar Thermal Power Plants

    Directory of Open Access Journals (Sweden)

    Jorge M. Llamas

    2017-08-01

    Full Text Available Currently, operating parabolic trough (PT solar thermal power plants, either solar-only or with thermal storage block, use the solar field as a heat transfer fluid (HTF thermal storage system to provide extra thermal capacity when it is needed. This is done by circulating heat transfer fluid into the solar field piping in order to create a heat fluid buffer. In the same way, by oversizing the solar field, it can work as an alternative thermal energy storage (TES system to the traditionally applied methods. This paper presents a solar field TES model for a standard solar field from a 50-MWe solar power plant. An oversized solar model is analyzed to increase the capacity storage system (HTF buffering. A mathematical model has been developed and different simulations have been carried out over a cycle of one year with six different solar multiples considered to represent the different oversized solar field configurations. Annual electricity generation and levelized cost of energy (LCOE are calculated to find the solar multiple (SM which makes the highest solar field thermal storage capacity possible within the minimum LCOE.

  14. Net Locality

    DEFF Research Database (Denmark)

    de Souza e Silva, Adriana Araujo; Gordon, Eric

    Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

  15. Net Neutrality

    DEFF Research Database (Denmark)

    Savin, Andrej

    2017-01-01

    Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else.......Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else....

  16. Planning a solar active house in Ticino with heat storage in slabs; Etude d'une maison solaire active avec stockage en dalles au Tessin

    Energy Technology Data Exchange (ETDEWEB)

    Pahud, D.

    2000-07-01

    A single-family house is planned in Tenero, Ticino, Switzerland, with the objective of integrating renewable energies in the space heating design. The space heating demand is reduced until the so-called 'Minergie' standard is met, so that the house can be heated by its 'activated' concrete plates. An 'active plate' is a concrete plate in which pipes have been fixed for the circulation of a heat transfer fluid, acting as a heat emitter with a very large heat capacity, used as a heat storage device for a solar heating system. The building and heating system are studied by means of computerized simulation. The TRNSYS system simulation programme is used to set up a calculation tool for the whole system including the building, the active concrete plates and the solar heating system. The dynamic simulations are used to confirm the technical feasibility of the studied concept, to establish the thermal performance of the solar heating system and of the house, and to compare various variants involving an uncovered solar absorber, a larger active concrete plate area and the influence of passive solar gains on the solar heating system. Three variants are studied to reduce the specific energy demand of the house. The additional costs associated with each measure (improved house envelope, fan-assisted balanced ventilation with heat recovery, solar domestic hot water, solar space heating and increased window area) are estimated. The energy cost associated with each measure is assessed, as well as the effective annual additional cost, which also takes into account the increase in price of the auxiliary heat.

  17. Evaluation of three energy balance-based evaporation models for estimating monthly evaporation for five lakes using derived heat storage changes from a hysteresis model

    NARCIS (Netherlands)

    Duan, Z.; Bastiaanssen, W.G.M.

    2017-01-01

    The heat storage changes (Qt) can be a significant component of the energy balance in lakes, and it is important to account for Qt for reasonable estimation of evaporation at monthly and finer timescales if the energy balance-based evaporation models are used. However, Qt has been often neglected in

  18. Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the activity

    Science.gov (United States)

    The objectives of this study were to investigate the influence of heat (70oC for 5 min) and cold-storage (4oC up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella Typhimurium DT104 in ground pork and to evaluate the activi...

  19. Improved performance of Heat Pumps helps to use full potential of subsurface space for Aquifer Thermal Energy Storage : Use it or loose it

    NARCIS (Netherlands)

    Bloemendal, J.M.; Jaxa-Rozen, M.; Rostampour Samarin, V.

    2017-01-01

    The application of seasonal Aquifer Thermal Energy Storage (ATES) contributes to meet goals for energy savings and greenhouse gas (GHG) emission reductions. Heat pumps have a crucial position in ATES systems because they dictate the operation scheme of the ATES wells and therefore play an important

  20. Effects of heat stress and probiotic supplementation on protein functionality and oxidative stability of ground chicken leg meat during display storage

    Science.gov (United States)

    The objective of this study was to evaluate effects of heat stress and probiotic supplementation on protein functionality and oxidative stability of ground chicken leg meat during display storage. Two hundred and forty 1-day-old male chicks (5 bird per pen) were randomly subjected to four treatments...

  1. Novel functional materials from renewable lipids: Amphiphilic antimicrobial polymers and latent heat thermal energy storage

    Science.gov (United States)

    Floros, Michael Christopher

    Vegetable oils represent an ideal and renewable feedstock for the synthesis of a variety of functional materials. However, without financial incentive or unique applications motivating a switch, commercial products continue to be manufactured from petrochemical resources. Two different families of high value, functional materials synthesized from vegetable oils were studied. These materials demonstrate superior and unique performance to comparable petrochemical analogues currently on the market. In the first approach, 3 amphiphilic thermoplastic polytriazoles with differing lipophilic segment lengths were synthesized in a polymerization process without solvents or catalysts. Investigation of monomer structure influence on the resultant functional behaviour of these polymers found distinctive odd/even behaviour reliant on the number of carbon atoms in the monomers. Higher concentrations of triazole groups, due to shorter CH2 chains in the monomeric dialkynes, resulted in more brittle polymers, displaying higher tensile strengths but reduced elongation to break characteristics. These polymers had similar properties to commercial petroleum derived thermoplastics. One polymer demonstrated self-assembled surface microstructuring, and displayed hydrophobic properties. Antimicrobial efficacy of the polymers were tested by applying concentrated bacterial solutions to the surfaces, and near complete inhibition was demonstrated after 4 hours. Scanning electron microscope images of killed bacteria showed extensive membrane damage, consistent with the observed impact of other amphiphilic compounds in literature. These polytriazoles are suited for applications in medical devices and implants, where major concerns over antibiotic resistance are prevalent. In the second approach, a series of symmetric, saturated diester phase change materials (PCMs) were also synthesized with superior latent heat values compared to commercial petrochemical analogues. These diesters exhibit

  2. THADA Regulates the Organismal Balance between Energy Storage and Heat Production.

    Science.gov (United States)

    Moraru, Alexandra; Cakan-Akdogan, Gulcin; Strassburger, Katrin; Males, Matilda; Mueller, Sandra; Jabs, Markus; Muelleder, Michael; Frejno, Martin; Braeckman, Bart P; Ralser, Markus; Teleman, Aurelio A

    2017-04-10

    Human susceptibility to obesity is mainly genetic, yet the underlying evolutionary drivers causing variation from person to person are not clear. One theory rationalizes that populations that have adapted to warmer climates have reduced their metabolic rates, thereby increasing their propensity to store energy. We uncover here the function of a gene that supports this theory. THADA is one of the genes most strongly selected during evolution as humans settled in different climates. We report here that THADA knockout flies are obese, hyperphagic, have reduced energy production, and are sensitive to the cold. THADA binds the sarco/ER Ca2+ ATPase (SERCA) and acts on it as an uncoupler. Reducing SERCA activity in THADA mutant flies rescues their obesity, pinpointing SERCA as a key effector of THADA function. In sum, this identifies THADA as a regulator of the balance between energy consumption and energy storage, which was selected during human evolution. Copyright © 2017 The Francis Crick Institute. Published by Elsevier Inc. All rights reserved.

  3. Analysis of the influence of operating conditions and geometric parameters on heat transfer in water-paraffin shell-and-tube latent thermal energy storage unit

    Energy Technology Data Exchange (ETDEWEB)

    Trp, Anica; Lenic, Kristian; Frankovic, Bernard [Faculty of Engineering, University of Rijeka, Vukovarska 58, HR-51000 Rijeka (Croatia)

    2006-11-15

    A transient heat transfer phenomenon during charging and discharging of the shell-and-tube latent thermal energy storage system has been analysed in this paper. The mathematical model, regarding the conjugate problem of transient forced convection and solid-liquid phase change heat transfer based on the enthalpy formulation, has been presented. A fully implicit two-dimensional control volume FORTRAN computer code has been developed for solving governing equations with initial and boundary conditions. The numerical model is validated with experimental data obtained by experimental investigations that have been performed on the test unit with technical grade paraffin as the phase change material (PCM) and water as the heat transfer fluid (HTF). Numerical predictions match the experimental results. This pointed out that the presented numerical procedure could be accurately used for transient heat transfer simulation. A series of numerical calculations have been done in order to analyse the influence of several HTF operating conditions and several geometric parameters on the heat transfer process inside the water-paraffin shell-and-tube latent thermal energy storage (LTES) unit. Numerical results, which could be used for operating conditions and geometry optimization, provide guidelines for the design of the latent thermal energy storage system. (author)

  4. Solarly supported combined heat and power generation with a seasonal heat storage. Danish pilot project Sunstore 4; Solar unterstuetzte Kraft-Waerme-Kopplung mit saisonalem Waermespeicher. Daenisches Pilotprojekt Sunstore 4

    Energy Technology Data Exchange (ETDEWEB)

    Pauschinger, Thomas; Schmidt, Thomas [Steinbeis Forschungsinstitut fuer Solare und Zukunftsfaehige Thermische Energiesysteme, Stuttgart (Germany)

    2013-05-15

    In the year 2012, a new plant concept for the local district heating system was implemented in Marstal on the Danish island Aeroe. This concept is based on 100 % renewable energy. The central components are a solar thermal plant with a rated performance of 23.4 MW{sub th}, a seasonal heat storage with a water content of 75,000 m{sup 3} and a biomass cogeneration plant with an ORC system. The total concept called Smart District Heating enables an economically attractive participation at the balancing energy market for electricity.

  5. Food Safety Nets:

    OpenAIRE

    Haggblade, Steven; Diallo, Boubacar; Staatz, John; Theriault, Veronique; Traoré, Abdramane

    2013-01-01

    Food and social safety nets have a history as long as human civilization. In hunter gatherer societies, food sharing is pervasive. Group members who prove unlucky in the short run, hunting or foraging, receive food from other households in anticipation of reciprocal consideration at a later time (Smith 1988). With the emergence of the first large sedentary civilizations in the Middle East, administrative systems developed specifically around food storage and distribution. The ancient Egyptian...

  6. Preparation and characterization of novel anion phase change heat storage materials.

    Science.gov (United States)

    Hong, Wei; Lil, Qingshan; Sun, Jing; Di, Youbo; Zhao, Zhou; Yu, Wei'an; Qu, Yuan; Jiao, TiFeng; Wang, Guowei; Xing, Guangzhong

    2013-10-01

    In this paper, polyurethane phase change material was successfully prepared with TDI with BDO for hard segments and PEG for soft segments. Moreover, based on this the solid-solid phase change material, A-PCM1030 which can release anions was prepared with the successful addition of anion additives A1030 for the first time. Then the test of the above material was conducted utilizing FT-IR, DSC, TEM, WAXD and Air Ion Detector. The Results indicated that the polyurethane phase change material possesses excellent thermal stability since there was no appearance of liquid leakage and phase separation after 50 times warming-cooling thermal cycles. It also presented reversibility on absorbing and releasing heat. In addition, adding a little A1030 can increase the thermal stability and reduce phase transition temperatures, as well as reduce the undercooling of the polyurethane phase change material. In addition, the anion test results suggested that the supreme amount of anion released by A-PCM1030 could reach 2510 anions/cm3 under dynamic conditions, which is beneficial for human health.

  7. Radiant heat testing of the H1224A shipping/storage container

    Energy Technology Data Exchange (ETDEWEB)

    Harding, D.C.; Bobbe, J.G.; Stenberg, D.R.; Arviso, M.

    1994-05-01

    H1224A weapons containers have been used for years by the Departments of Energy and Defense to transport and store W78 warhead midsections. Although designed to protect the midsections only from low-energy impacts, a recent transportation risk assessment effort has identified a need to evaluate the container`s ability to protect weapons in more severe accident environments. Four radiant heat tests were performed: two each on an H1224A container (with a Mk12a Mod 6c mass mock-up midsection inside) and two on a low-cost simulated H1224A container (with a hollow Mk12 aeroshell midsections inside). For each unit tested, temperatures were recorded at numerous points throughout the container and midsection during a 4-hour 121{degrees}C (250{degrees}F) and 30-minute 1010{degrees}C (1850{degrees}F) radiant environment. Measured peak temperatures experienced by the inner walls of the midsections as a result of exposure to the high-temperature radiant environment ranged from 650{degrees} C to 980{degrees} C (1200{degrees} F to 1800{degrees}F) for the H1224A container and 770 {degrees} to 990 {degrees}C (1420{degrees} F to 1810{degrees}F) for the simulated container. The majority of both containers were completely destroyed during the high-temperature test. Temperature profiles will be used to benchmark analytical models and predict warhead midsection temperatures over a wide range of the thermal accident conditions.

  8. Achievement report for fiscal 2000 on the phase II research and development for hydrogen utilizing international clean energy system technology (WE-NET). Task 9. Development of liquid hydrogen transportation and storage technologies - 1; 2000 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET) dai 2 ki kenkyu kaihatsu. Task 9. Ekitai suiso yuso chozo gijutsu no kaihatsu - 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    This paper describes the achievements in fiscal 2000 from the development of liquid hydrogen transportation and storage technologies. Discussions were given on the following three types of specimens as the heat insulation performance test structures: the vacuum panel type (polyurethane foam coated with SUS sheet, while the inside is kept in the vacuum state); the solid vacuum type (combination of polyurethane foam with vacuum heat insulation); and the powder under normal pressure type (a structure in which the ambient of powder pearlite heat insulating material becomes the atmospheric pressure, whereas a SUS case is set up to separate vacuum layer of the test apparatus from atmosphere layer of the specimen, with the SUS case filled with pearlite). Adding the two types of specimens used in the previous fiscal year, five test specimens in total were discussed on the result of the performance tests to advance the database management. As a low temperature strength test for the insulating materials, the compression test was performed on a microsphere being a kind of solid vacuum (normal pressure) heat insulating materials at room temperature, the liquid nitrogen temperature and in liquid hydrogen atmosphere. The compression strength under liquid hydrogen is 1,044 MPa, which is two times greater than the normal temperature strength of 496 MPa, representing the compression strength rising in proportion with temperature drop. Problems were extracted in developing a small capacity liquid hydrogen transportation and storage system. (NEDO)

  9. Development and evaluation of materials for thermochemical heat storage based on the CaO/CaCO3 reaction couple

    Science.gov (United States)

    Sakellariou, Kyriaki G.; Tsongidis, Nikolaos I.; Karagiannakis, George; Konstandopoulos, Athanasios G.; Baciu, Diana; Charalambopoulou, Georgia; Steriotis, Theodore; Stubos, Athanasios; Arlt, Wolfgang

    2016-05-01

    The current work relates to the development of synthetic calcium oxide (CaO) based compositions as candidate materials for energy storage under a cyclic carbonation/decarbonation reaction scheme. Although under such a cyclic scheme the energy density of natural lime based CaO is high (˜ 3MJ/kg), the particular materials suffer from notable cycle-to-cycle deactivation. To this direction, pure CaO and CaO/Al2O3 composites have been prepared and preliminarily evaluated under the suggested cyclic carbonation/decarbonation scheme in the temperature range of 600-800°C. For the composite materials, Ca/Al molar ratios were in the range between 95/5 and 52/48 and upon calcination the formation of mixed Ca/Al phases was verified. The preliminary evaluation of materials studied was conducted under 3 carbonation/decarbonation cycles and the loss of activity for the case of natural CaO was obvious. Synthetic materials with superior stability/capture c.f. natural CaO were further subjected to multi-cyclic carbonation/decarbonation, via which the positive effect of alumina addition was made evident. Selected compositions exhibited adequately high CO2 capture capacity and stable performance during multi-cyclic operation. Moreover, this study contains preliminary experiments referring to proof-of-principle validation of a concept based on the utilization of a CaO-based honeycomb reactor/heat exchanger preliminary design. In particular, cordierite monolithic structures were coated with natural CaO and in total 11 cycles were conducted. Upon operation, clear signs of heat dissipation by the imposed flow in the duration of the exothermic reaction step were identified.

  10. Large heat storage tank for load management nd implementation of ambient heat. District heating networks based on combined heat and power; Grosswaermespeicher zum Lastmanagement und zur Einbindung von Umweltenergie. Auf KWK basierende Fernwaermenetze

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Sebastian; Rhein, Martin; Ruehling, Karin [Technische Universitaet Dresden (Germany). Inst. fuer Energietechnik

    2013-06-15

    The district heating based on combined heat and power is a transitional technology on the way to the supply of Germany with renewable energy. In the next years, this transitional technology can only be maintained and expanded when marketability is given. Therefore an appropriate combination has to be found from investment measures. Together with new aspects in the management strategy, these investment measures should significantly improve the marketability. The investment measures also aims to enable a primary energetic, appropriate combination of natural gas-based combined heat and power, renewable energy sources (solar thermal energy, ambient heat) and heat pump technology.

  11. Numerical modelling of a 100-Wh lab-scale thermochemical heat storage system for concentrating solar power plants

    Science.gov (United States)

    de Miguel, Sandra Álvarez; Bellan, Selvan; de María, J. M. García; González-Aguilar, José; Romero, Manuel

    2016-05-01

    Dispatchable electricity generation on demand is a fundamental issue for commercial deployment of Concentrated Solar Power (CSP) plants. One of the promising routes to overcome the intermittence of the solar resource is the use of thermochemical energy storage systems based on redox reactions of metal oxides. Different metal oxides might potential candidates as storing material depending on the foreseen working temperature range. In the framework of the FP7 European project TCSPower, a particle-based reactor is used to analyze this type of materials. The lab-scale thermochemical reactor is initially tested using an inert material (alumina particles) instead of reactants in order to study its thermal performance. Thermocouples installed inside the system at various positions monitor the experiments. A three dimensional numerical model is developed to investigate the flow and heat transfer in the reactor. The governing equations - mass, momentum and energy conservation - are solved by the finite element method in the commercial software COMSOL Multiphysics. Simulations are performed for the experimental conditions. Experimentally measured and numerically predicted temperature profiles at various locations inside the system are compared and presented in this paper.

  12. Analysis of the effects of storage conditions on the preservation of soybean quality and the prevention of the self-heating process and the occurrence of fires

    Directory of Open Access Journals (Sweden)

    Milanko Verica J.

    2012-01-01

    Full Text Available After harvest, oilseed raw materials must be stored for a longer or shorter period of time before further processing. The task of storage is the safekeeping of the stored material with a minimal loss in quality. In order to preserve wet grain until processing, it is necessary to provide proper storage conditions. For this purpose, storage in the atmosphere of inert gases as well as storage in hermetically closed storages is applied. Such method is uncommon for oil cultures in domestic practice. Experimental research, analyzed in this paper, with emphasis on the effects of storage conditions on the preservation of soybean grain quality and the prevention of possibilities of the occurrence of the self-heating and self-ignition process, confirms the advantages of application of such method of storage for soybean grain. Soybean with the moisture content of 10.99% and 16.96% is stored in steel semi-industrial silo cells with carbon-dioxide atmosphere, and in hermetically sealed cell. The changes in temperature in the silo cells, changes in moisture content and discoloration of the soybean grains, as well as the amount of oil and protein in the grain were monitored during the experiment. The quality of the oil in grain was determined through the content of free fatty acids. The results of the research showed that, during longer period of time (216 days, the quality of the soybean grain in the sample with higher moisture content (16,96% was preserved when storage was performed in carbon dioxide atmosphere. The storage of wet grain in a hermetically closed cell, in relation to the grain kept in carbon dioxide atmosphere, did not record significant differences in the examined indicators. Since the storage under controlled conditions did not result in the development of processes that would lead to the spontaneous heating of the soybean mass, the recommendation is to introduce such storage method for oilseed raw materials into domestic practice, with the

  13. Modelling of a solar stove: small scale concentrating system with heat storage: potential for cooking in rural areas, Zimbabwe

    Energy Technology Data Exchange (ETDEWEB)

    Chikukwa, Actor

    2007-10-15

    programme is to simulate the heat transfer mechanisms taking place within the fibrous receiver during operation. The predicted results are then presented and discussed in detail. The transportation of the hot air from the receiver, the ceding of its sensible energy to rockbed thermal storage and insulation are deliberated in chapter 5. Another major computer programme that models these processes is written, in which case, results for different inputs are discussed and compared. The need to devise an airpump capable of adjusting the mass flow rate in order to sustain a constant inlet air temperature to the storage is highlighted. Chapter 6 describes the design of the hotplates and their incorporation to the storage unit. The premise on which the third major computer model in this work is discussed in detail. This simulation programme attempts to model a cooking process, in which case, the thermal storage is simultaneously discharged. The results are presented and an overview of the merits of a successful system are briefly discussed. Finally, major conclusions, recommendations and areas for further study are given(Author). refs., figs., tabs

  14. The GEOSER project - short-term storage of solar heat in horticultural greenhouses; GEOSER Stockage solaire a court terme en serres horticoles

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.; Lachal, P.; Gil, J. [University of Geneva, Centre Universitaire d' Etude des Problemes de l' Energie (CUEPE), Carouge (Switzerland); Jaboyedoff, P. [Sorane, Lausanne (Switzerland); Reist, A. [Centre des Fougeres, Station de recherches en production vegetale de Changins, Conthey (Switzerland); Danloy, L. [Danloy Luc, Meyrin (Switzerland)

    2002-07-01

    Today, horticultural greenhouses are significantly contributing to fresh victualling supply. In a temperate climate they have to be more or less permanently heated to make all-year round production possible. To reduce energy consumption, greenhouses were successively improved since the 70es, beginning with their envelope and heat distribution systems. The next step was the development of storage/heat-recovery systems for solar heat in greenhouses. Here, mainly two types are encountered: air/ground heat exchangers placed under the greenhouse ground; air/water heat exchangers in the greenhouse, connected to an underground water store. In the present report the two types are compared in a side-by-side experiment including a third greenhouse with a conventional gas heating and heat distribution system, as a reference. Comprehensive energy balances including parasitic energy consumption (electricity) are presented. In the three greenhouses the same agricultural programme was carried out. The comparative evaluation included this aspect as well. Computerized simulations supplemented the analysis, enabling a parametric study and the evaluation of potential improvements towards optimal systems.

  15. Natural and Artificial Methods for Regeneration of Heat Resources for Borehole Heat Exchangers to Enhance the Sustainability of Underground Thermal Storages: A Review

    Directory of Open Access Journals (Sweden)

    Tomasz Sliwa

    2015-09-01

    Full Text Available The concept of borehole heat exchanger (BHE field exploitation is described, along with problems regarding the sustainability of heat resources in rock masses. A BHE field sometimes has problems with the stability of the heat carrier temperature during long-term exploitation. The main reason for this is an insufficient heat stream with which to transfer heat by conduction in rock. Possibilities for the regeneration of heat in rock masses, based on experiences at the Geoenergetics Laboratory (Drilling, Oil and Gas Faculty, AGH University of Science and Technology, are described.

  16. Efficiently modelling urban heat storage: an interface conduction scheme in an urban land surface model (aTEB v2.0)

    Science.gov (United States)

    Lipson, Mathew J.; Hart, Melissa A.; Thatcher, Marcus

    2017-03-01

    Intercomparison studies of models simulating the partitioning of energy over urban land surfaces have shown that the heat storage term is often poorly represented. In this study, two implicit discrete schemes representing heat conduction through urban materials are compared. We show that a well-established method of representing conduction systematically underestimates the magnitude of heat storage compared with exact solutions of one-dimensional heat transfer. We propose an alternative method of similar complexity that is better able to match exact solutions at typically employed resolutions. The proposed interface conduction scheme is implemented in an urban land surface model and its impact assessed over a 15-month observation period for a site in Melbourne, Australia, resulting in improved overall model performance for a variety of common material parameter choices and aerodynamic heat transfer parameterisations. The proposed scheme has the potential to benefit land surface models where computational constraints require a high level of discretisation in time and space, for example at neighbourhood/city scales, and where realistic material properties are preferred, for example in studies investigating impacts of urban planning changes.

  17. RESTful NET

    CERN Document Server

    Flanders, Jon

    2008-01-01

    RESTful .NET is the first book that teaches Windows developers to build RESTful web services using the latest Microsoft tools. Written by Windows Communication Foundation (WFC) expert Jon Flanders, this hands-on tutorial demonstrates how you can use WCF and other components of the .NET 3.5 Framework to build, deploy and use REST-based web services in a variety of application scenarios. RESTful architecture offers a simpler approach to building web services than SOAP, SOA, and the cumbersome WS- stack. And WCF has proven to be a flexible technology for building distributed systems not necessa

  18. More with thermal energy storage. Report 8. Autonomous heating. Autonomous development of ground temperature. Final report; Meer met bodemenergie. Rapport 8. Autonome opwarming. Autonome ontwikkeling bodemtemperatuur. Eindrapport

    Energy Technology Data Exchange (ETDEWEB)

    Drijver, B. [IF Technology, Arnhem (Netherlands)

    2012-03-30

    The project More With Thermal Energy Storage (MMB, abbreviated in Dutch) focuses on knowledge gaps and potential opportunities regarding open systems. The main questions to be answered are: (1) What effects (hydrological, thermal, microbiological and chemical) occur in the soil system by application of thermal energy storage; (2) Which technical options are available for a sustainable integration of thermal energy storage in the water and energy chain?; (3) Is it possible to achieve multiple objectives by using smart combinations? The project is organized in different work packages. In work package 2, the effects of individual and collective thermal energy storage storage systems on subsoils and the environment are determined. In work package 3 the opportunities for thermal energy storage and soil remediation are examined, while in work package 4 the focus is on new sustainable combinations of heat and cold storage. Work package 1 is the umbrella part where communication and policy of and participation in MMB are the main subjects. This report contains an analysis of the thermal impact of climate change and urbanization on the soil temperature. Attention is paid to the autonomous heating of the subsurface that occurred since 1900 and that still may be expected up to 2040. A distinction is made between rural areas, where only the climate change plays a role, and urban areas, where the UHI effect (Urban Heat Island) is of importance [Dutch] Het project Meer Met Bodemenergie (MMB) richt zich op het invullen van kennisleemtes en mogelijke kansen ten aanzien van open systemen. De belangrijkste vragen waarop het onderzoeksprogramma MMB antwoord geeft zijn: (1) Welke effecten (hydrologisch, thermisch, microbiologisch en chemisch) treden op in het bodemsysteem bij toepassing van bodemenergie?; (2) Welke technische mogelijkheden zijn er voor het duurzaam inpassen van bodem-energie in de water- en energieketen?; (3) Is het mogelijk om meerdere doelstellingen tegelijk te

  19. On the Convenience of Using Simulation Models to Optimize the Control Strategy of Molten-Salt Heat Storage Systems in Solar Thermal Power Plants

    Directory of Open Access Journals (Sweden)

    Miguel J. Prieto

    2017-07-01

    Full Text Available Thermal oil has been used as heat transfer fluid in many solar thermal power plants, which also use molten salts as thermal energy storage system. Since the engineering of these plants is relatively new, control of the thermal energy storage system is currently achieved in manual or semiautomatic ways, controlling its variables with proportional-integral-derivative (PID regulators. Once the plant is running, it is very difficult to obtain permission to try new control strategies. Hence, most plants keep running on these simple, sometimes inefficient control algorithms. This paper explores the results obtained with different control strategies implemented on a complete model of energy storage systems based on molten salt. The results provided by the model allow the optimum control strategy to be selected. Comparison of the results obtained by simulation of these control strategies and actual results obtained from a real plant, confirm the accuracy of the selection made.

  20. Multi-period MINLP model for optimising operation and structural changes to CHP plants in district heating networks with long-term thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Tveit, Tor-Martin; Savola, Tuula; Fogelholm, Carl-Johan [Helsinki University of Technology, Faculty of Engineering and Architecture, Department of Energy Technology, P.O. Box 4400, FI-02015 TKK (Finland); Gebremedhin, Alemayehu [Linkoeping University, IEI, Division of Energy Systems, SE-581 83 Linkoeping (Sweden)

    2009-03-15

    By using thermal storages it is possible to decouple the generation of power and heat, and it can also lead to an reduction in investments, as the storage can be used to cover the peak load periods. This work presents a MINLP model that can be used for analysing new investments and the long-term operation of CHP plants in a district heating network with long-term thermal storage. The model presented in this work includes the non-linear off-design behaviour of the CHP plants as well as a generic mathematical model of the thermal storage, without the need to fix temperatures and pressure. The model is formulated in such a way that it is suitable for deterministic MINLP solvers. The model is non-convex, and subsequently global optimality cannot be guaranteed with local solvers. In order to reduce the chance of obtaining a poor local optimum compared to the global optimum, the model should be solved many times with the initial values varying randomly. It is possible to extract a lot of results from the model, for instance total annual profit, the optimal selection of process options, mass flow through the plant, and generated power from each plant. The formulation of the model makes it suitable for deterministic MINLP solvers. (author)

  1. Methods of increasing net work output of organic Rankine cycles for low-grade waste heat recovery with a detailed analysis using a zeotropic working fluid mixture and scroll expander

    Science.gov (United States)

    Woodland, Brandon Jay

    An organic Rankine cycle (ORC) is a thermodynamic cycle that is well-suited for waste heat recovery. It is generally employed for waste heat with temperatures in the range of 80 °C -- 300 °C. When the application is strictly to convert waste heat into work, thermal efficiency is not recommended as a key performance metric. In such an application, maximization of the net power output should be the objective rather than maximization of the thermal efficiency. Two alternative cycle configurations that can increase the net power produced from a heat source with a given temperature and flow rate are proposed and analyzed. These cycle configurations are 1) an ORC with two-phase flash expansion and 2) an ORC with a zeotropic working fluid mixture (ZRC). A design-stage ORC model is presented for consistent comparison of multiple ORC configurations. The finite capacity of the heat source and heat sink fluids is a key consideration in this model. Of all working fluids studied for the baseline ORC, R134a and R245fa yield the highest net power output from a given heat source. Results of the design-stage model indicate that the ORC with two-phase flash expansion offers the most improvement over the baseline ORC. However, the level of improvement that could be achieved in practice is highly uncertain due to the requirement of highly efficient two-phase expansion. The ZRC shows improvement over the baseline as long as the condenser fan power requirement is not negligible. At the highest estimated condenser fan power, the ZRC shows the most improvement, while the ORC with flash expansion is no longer beneficial. The ZRC was selected for detailed study because it does not require two-phase expansion. An experimental test rig was used to evaluate baseline ORC performance with R134a and with R245fa. The ZRC was tested on the same rig with a mixture of 62.5% R134a and 37.5% R245fa. The tested expander is a minimally-modified, of-the-shelf automotive scroll compressor. The high

  2. Petri Nets

    Indian Academy of Sciences (India)

    Associate Professor of. Computer Science and. Automation at the Indian. Institute of Science,. Bangalore. His research interests are broadly in the areas of stochastic modeling and scheduling methodologies for future factories; and object oriented modeling. GENERAL I ARTICLE. Petri Nets. 1. Overview and Foundations.

  3. Petri Nets

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 8. Petri Nets - Overview and Foundations. Y Narahari. General Article Volume 4 Issue 8 August 1999 pp ... Author Affiliations. Y Narahari1. Department ot Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India.

  4. Heat

    CERN Document Server

    Lawrence, Ellen

    2016-01-01

    Is it possible to make heat by rubbing your hands together? Why does an ice cube melt when you hold it? In this title, students will conduct experiments to help them understand what heat is. Kids will also investigate concepts such as which materials are good at conducting heat and which are the best insulators. Using everyday items that can easily be found around the house, students will transform into scientists as they carry out step-by-step experiments to answer interesting questions. Along the way, children will pick up important scientific skills. Heat includes seven experiments with detailed, age-appropriate instructions, surprising facts and background information, a "conclusions" section to pull all the concepts in the book together, and a glossary of science words. Colorful, dynamic designs and images truly put the FUN into FUN-damental Experiments.

  5. Thermal performance analysis of a solar heating plant

    DEFF Research Database (Denmark)

    Fan, Jianhua; Huang, Junpeng; Andersen, Ola Lie

    Detailed measurements were carried out on a large scale solar heating plant located in southern Denmark in order to evaluate thermal performances of the plant. Based on the measurements, energy flows of the plant were evaluated. A modified Trnsys model of the Marstal solar heating plant...... was developed to calculate thermal performances of the plant. In the Trnsys model, three solar collector fields with a total solar collector area of 33,300 m2, a seasonal water pit heat storage of 75,000 m3, a simplified CO2 HP, a simplified ORC unit and a simplified wood chip boiler were included. The energy...... consumption of the district heating net was modeled by volume flow rate and given forward and return temperatures of the district heating net. Weather data from a weather station at the site of the plant were used in the calculations. The Trnsys calculated yearly thermal performance of the solar heating plant...

  6. Development of hybrid wood-fired heating systems - Storage oven with water absorber; Entwicklung neuartiger Holz-Hybridheizsysteme. Speicheroefen mit Wasserabsorber

    Energy Technology Data Exchange (ETDEWEB)

    Huber, H.; Frei, B.; Kropf, S. [Hochschule fuer Technik und Architektur (HTA), Lucerne (Switzerland); Macquat, Y.; Gaegauf, Ch. [Oekozentrum, Langenbruck (Switzerland)

    2002-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project involving the development of a wood-fired storage oven fitted with an absorber that collects heat from the storage oven and distributes it by means of a conventional heating system. The results of tests made on a functional prototype and a real-life oven are presented. Also, a simulation model that was created on the basis of the functional prototype and the parameters of the real-life oven is introduced. The results obtained for various combinations of parameters such as distance between absorber piping, distance between absorber and room, firing intervals and type of integration into the building's heating system are discussed. Three standard variants for the integration in heating systems are presented, including the necessary safety equipment. The results of safety tests on a demonstration model are presented. The authors state that certain points such as the dimensioning of expansion vessels and component configuration must be looked at with particular care and that this type of hybrid oven could be useful for low-energy-consumption housing, whereby a combination with solar installations should be considered.

  7. Sediment accumulation and net storage determined by field observation and numerical modelling for an extensive tropical floodplain: Beni River, Bolivian Llanos

    Science.gov (United States)

    Schwendel, Arved; Aalto, Rolf; Nicholas, Andrew

    2014-05-01

    Lowland floodplains in subsiding basins form major depocentres responsible for the storage and cycling of large quantities of fine sediment and associated nutrients and contaminants. Obtaining reliable estimates of sediment storage in such environments is problematic due to the high degree of spatial and temporal variability exhibited by overbank sediment accumulation rates, combined with the logistical difficulties inherent in sampling locations far away from the channel. Further complexity is added by the high channel mobility, which recycles sediment and reconfigures the relationships between channel and floodplain morphology, sediment transport and overbank sedimentation. Estimates of floodplain accretion can be derived using a range of numerical sedimentation models of varying complexity. However, data required for model calibration are rarely available for the vast floodplains associated with tropical rivers. We present results from a study of channel-floodplain sediment exchange fluxes on the Rio Beni, a highly dynamic, tropical sand-bed tributary of the Amazon in northern Bolivia. The Beni transports high concentrations of suspended sediment, generated in the river's Andean headwaters, and disperses this material across an extensive floodplain wetland that experiences annual inundation over an area of up to 40000 km2. We utilise estimates of overbank sedimentation rates over the past century derived from 210Pb analysis of floodplain sediment cores collected along a 375 km length of channel, including sampling a range of channel-floodplain configurations within the channel belt and on the distal floodplain (up to 60 km from the channel). These data are used to investigate spatial and temporal variations in rates of floodplain sediment accumulation for a range of grain sizes. Specifically, we examine relationships between sedimentation rate and distance from the channel, and characterise within channel belt variability in sedimentation linked to patterns of

  8. Thermal Analysis of a Thermal Energy Storage Unit to Enhance a Workshop Heating System Driven by Industrial Residual Water

    National Research Council Canada - National Science Library

    Wenqiang Sun; Zuquan Zhao; Yanhui Wang

    2017-01-01

    .... However, the majority of applicable waste heat resources are high-grade or stable thermal energy, while the low-grade or unstable waste heat resources, especially low-temperature industrial residual water (IRW...

  9. Effect of Heat and Electricity Storage and Reliability on Microgrid Viability:A Study of Commercial Buildings in California and New York States

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy; Coffey, Brian; Aki, Hirohisa

    2008-12-01

    In past work, Berkeley Lab has developed the Distributed Energy Resources Customer Adoption Model (DER-CAM). Given end-use energy details for a facility, a description of its economic environment and a menu of available equipment, DER-CAM finds the optimal investment portfolio and its operating schedule which together minimize the cost of meeting site service, e.g., cooling, heating, requirements. Past studies have considered combined heat and power (CHP) technologies. Methods and software have been developed to solve this problem, finding optimal solutions which take simultaneity into account. This project aims to extend on those prior capabilities in two key dimensions. In this research storage technologies have been added as well as power quality and reliability (PQR) features that provide the ability to value the additional indirect reliability benefit derived from Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid capability. This project is intended to determine how attractive on-site generation becomes to a medium-sized commercial site if economical storage (both electrical and thermal), CHP opportunities, and PQR benefits are provided in addition to avoiding electricity purchases. On-site electrical storage, generators, and the ability to seamlessly connect and disconnect from utility service would provide the facility with ride-through capability for minor grid disturbances. Three building types in both California and New York are assumed to have a share of their sensitive electrical load separable. Providing enhanced service to this load fraction has an unknown value to the facility, which is estimated analytically. In summary, this project began with 3 major goals: (1) to conduct detailed analysis to find the optimal equipment combination for microgrids at a few promising commercial building hosts in the two favorable markets of California and New York; (2) to extend the analysis capability of DER-CAM to include both heat and

  10. Summary Report for Concentrating Solar Power Thermal Storage Workshop: New Concepts and Materials for Thermal Energy Storage and Heat-Transfer Fluids, May 20, 2011

    Energy Technology Data Exchange (ETDEWEB)

    Glatzmaier, G.

    2011-08-01

    This document summarizes a workshop on thermal energy storage for concentrating solar power (CSP) that was held in Golden, Colorado, on May 20, 2011. The event was hosted by the U.S. Department of Energy (DOE), the National Renewable Energy Laboratory, and Sandia National Laboratories. The objective was to engage the university and laboratory research communities to identify and define research directions for developing new high-temperature materials and systems that advance thermal energy storage for CSP technologies. This workshop was motivated, in part, by the DOE SunShot Initiative, which sets a very aggressive cost goal for CSP technologies -- a levelized cost of energy of 6 cents per kilowatt-hour by 2020 with no incentives or credits.

  11. Simulation of the heat transfer of a irradiated fuel storage container with code CFD STAR- CCM+; Simulacion de la transferencia de calor de un contenedor de almacenamiento de combustible irradiado con el codigo CFD STAR-CCM+

    Energy Technology Data Exchange (ETDEWEB)

    Barrera matalla, J. E.; Hernandez Gomez, J.; Riverala Gurruchaga, J.

    2012-07-01

    Irradiated fuel has become an object of interest in the industry by the importance of ensuring its safety during long periods of storage time. New containers, stores, methods and codes will be used to ensure a suitable cooling and residual heat removal, and secure the safety of fuel elements in dry storage. The codes CFD (Computational Fluid Dynamics) have great potential to help in design of containers and stores, improving thermal-hydraulic performance and the extraction of heat generated.

  12. Application of a temperature selective heat storage tank to a solar system. Part 3. Solar heat collecting system; Ondo sentaku chikunetsuso no solar system eno tekiyo. 3. Shunetsu hoshiki ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Y. [Kanto Gakuin University, Yokohama (Japan); Kanayama, K. [Kitami Institute of Technology, Hokkaido (Japan)

    1996-10-27

    The tank system and tank-less system when the temperature selective heat storage tank is applied to a solar system were considered. In the tank system, the simulation shows that the annual supplementary heat consumption is reduced as the tank capacity becomes lower. The most suitable operating time set for determining the reference time is about five hours in winter and about nine hours in summer. The annual operating time is about 6.5 hours. In the tank-less system, the most suitable minimum flow rate per solar collector area of a heating medium in Tokyo and its districts is 10 L/hm{sup 2} for both three-step flow control and constant flow control. The tank-less system is slightly lower in annual supplementary heat consumption than the tank system. For the three-step flow control, a change in the annual supplementary heat consumption is lower than that in the minimum flow rate. For the constant flow control, however, the annual supplementary heat consumption rapidly increases when the flow rate more decreases than the optimum value. The number of pump start/stop counts for the three-step flow control is less than two times as high as for the constant flow control. 4 refs., 6 figs., 1 tab.

  13. Heat storage technology in Japan. ; Market and subject in period of maturity. Chikunetsu gijutsu. ; Seijukuki no shijo to kadai

    Energy Technology Data Exchange (ETDEWEB)

    Sue, N. (Mitsubishi Petrochemical Engineering Co. Ltd., Tokyo (Japan))

    1993-01-05

    By the recent power circumstances, especially along with an increase of the demand differentials between the daytime and nighttime accompanied with the extension of cooling and air conditioning, the commodity development especially for the cooling thermal reserve has become to be active. On the other hand, in addition, also the heat reserve technology as an effective utilization of the unutilized heat has been applied in practice in a form of the district cooling and heating, and moreover the heat reserve technology has been reviewed also for the countermeasures against the earth warming and the felon gas. While the heat reserve technology is old and new and has many technical elements anyone can participate, 3 functions-to be a low price, to take out easily at the consistent temperature, and moreover to be utilized free from care for a long time-required for the heat accumulator are not necessarily sufficient. The heat reserve technology is still in the less developed stage from a viewpoint of the cost and system volume compared with the main heat sources. The current state is that the market goes ahead and it is expected especially as a clear energy in the new generation, and recently the study as the heat shift medium between the summer and winter is commenced. Although the latent heat reserve technology will play the leading role in the market, the practical application of the chemical heat reserve will be soon as well. 5 refs., 8 figs., 5 tabs.

  14. Thermal storage studies for solar heating and cooling: applications using chemical heat pumps. Final report, September 15, 1979-April 15, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Offenhartz, P O.D.

    1981-04-01

    TRNSYS-compatible subroutines for the simulation of chemical heat pumps have been written, and simulations (including heating, cooling, and domestic hot water) have been performed for Washington, DC and Ft. Worth, Texas. Direct weekly comparisons of the H/sub 2/SO/sub 4//H/sub 2/O and CaCl/sub 2//CH/sub 3/OH cycles have been carried out. Projected performance of the NH/sub 4/NO/sub 3//NH/sub 3/ cycle has also been investigated, and found to be essentially identical to H/sub 2/SO/sub 4//H/sub 2/O. In all cases simulated, the solar collector is a fixed evacuated tube system, which is necessary because chemical heat pumps operate at higher solar collector temperatures (> 100/sup 0/C) than conventional solar systems. With standard residential loads, the chemical heat pumps performed surprisingly well. In the Ft. Worth climate, less than 45 m/sup 2/ of collectors were required to meet over 90% of the heating and cooling loads. In Washington, DC, the area required to meet the cooling load was smaller (as little as 20 m/sup 2/, depending on window shading), but was sufficient to meet only 50 to 60% of the heating load. However, gas-fired backup via the heat pump was quite effective in reducing fossil fuel consumption: the thermal COPs in the heating mode were in the range 1.6 to 1.7. Since chemical heat pumps are designed to reject heat at relatively high temperatures, they were also effective in providing domestic hot water, supplying ca. 70% of the DHW in summer, ca. 50% in winter, and nearly 100% in spring and fall.

  15. Single-family-residence solar heating--Carlsbad, New Mexico

    Science.gov (United States)

    1981-01-01

    Solar-heating and hot-water system includes 408 square feet of flat-plate air collectors, rock storage bin, energy transport system, air-to-water heat exchanger, controls, and hot-water preheat tank. Hot-air oil furnace supplies auxiliary space heating, and electricity powers air-handler blower and hot water preheat pump. For 12 month period, system provided 43 percent of space-heating and 53 percent of hot-water energy; net energy savings were 23.072 million Btu.

  16. Inventory of future power and heat production technologies. Partial report Energy storage; Inventering av framtidens el- och vaermeproduktionstekniker. Delrapport Energilagring

    Energy Technology Data Exchange (ETDEWEB)

    Messing, Lars; Lindahl, Sture (Gothia Power AB, Goeteborg (Sweden))

    2008-12-15

    In this report a survey of different techniques for storage of electrical energy. The following alternatives are described regarding method, characteristics, potential and economy. Batteries; Capacitors; Flywheels; Pump storage hydro power plants; Hydrogen gas generation; Air compression. Regarding evaluation of methods for storage of electrical energy. Battery storage: The development of Lithium-ion batteries are of great interest. In the present situation it is however difficult of classify battery storage as a good alternation in applications with frequent re-charging cycles and re-charging of large energy volumes. The batteries have limited life length compared to other alternatives. Also the power is limited at charging and discharging. Energy storage in capacitors: 'Super-capacitors' having large power capacity is considered to be of interest in applications where fast control of power is necessary. The ongoing development of based on carbon-nanotubes will increase the energy storage capacity compared with the today existing super-capacitors. This can in the future be an alternative to battery storage. Of further interest is also the idea to combine battery and capacitor based storage to achieve longer life-time of the batteries and faster power control. Flywheel energy storage: The energy storage capacity is relatively limited but power control can be fast. This system can be an alternative to capacitor based energy storage. Pump-storage hydro power plant: This type of energy storage is well suited and proven for time frame up to some days. In the Swedish power system there is today not any large demand of energy storage in this time frame as there is a large capacity in conventional hydro power plants with storage capacity. Pump-storage can however be of interest in the southern part of Sweden. In some operation stages the grid is loaded up to its limit due to large power transmission from the north. The pump-storage can reduce this power transfer

  17. The largest Swiss diffusion storage system - Geology, petrophysics, hydro-geology and experience gained from the realisation of heat probes; Groesster saisonaler Diffusionsspeicher der Schweiz D4 in Root (LU): Geologie, Petrophysik, Hydrogeologie und Erfahrungen mit der Realisation des Sondenfeldes

    Energy Technology Data Exchange (ETDEWEB)

    Keller, B.

    2007-07-15

    This article takes a look at a large heat-diffusion storage system that is to be implemented in stages at a business and innovation centre in Root, near Lucerne in Switzerland. The aim is to meet 50 percent of energy needs using renewable energy. Apart from conventional oil and gas-fired systems, a combined heat and power (CHP) unit, heat and cold storage, a solar roof and photovoltaics, a seasonal underground diffusion storage system is used. This storage system is 'filled' with heat in summer from the roof and waste heat. It then functions in winter as a heat source. The system features two fields of 49, 160 metre-long heat probes that use a volume of 376,000 cubic metres of rock. The dimensioning of the rock-storage system was simulated using the PILESIM program and the first field was implemented in 2001. A geological overview is presented and the physical properties of the rock structures used are discussed. The temperature profile measured is presented and the precautions taken as a result of the possibility of meeting pockets of natural gas are discussed. Know-how gained from the implementation of the first probe field is discussed.

  18. Thermophysical Characterization of MgCl₂·6H₂O, Xylitol and Erythritol as Phase Change Materials (PCM) for Latent Heat Thermal Energy Storage (LHTES).

    Science.gov (United States)

    Höhlein, Stephan; König-Haagen, Andreas; Brüggemann, Dieter

    2017-04-24

    The application range of existing real scale mobile thermal storage units with phase change materials (PCM) is restricted by the low phase change temperature of 58 ∘ C for sodium acetate trihydrate, which is a commonly used storage material. Therefore, only low temperature heat sinks like swimming pools or greenhouses can be supplied. With increasing phase change temperatures, more applications like domestic heating or industrial process heat could be operated. The aim of this study is to find alternative PCM with phase change temperatures between 90 and 150 ∘ C . Temperature dependent thermophysical properties like phase change temperatures and enthalpies, densities and thermal diffusivities are measured for the technical grade purity materials xylitol (C 5 H 12 O 5 ), erythritol (C 4 H 10 O 4 ) and magnesiumchloride hexahydrate (MCHH, MgCl 2 · 6H 2 O). The sugar alcohols xylitol and erythritol indicate a large supercooling and different melting regimes. The salt hydrate MgCl 2 · 6H 2 O seems to be a suitable candidate for practical applications. It has a melting temperature of 115.1 ± 0.1 ∘ C and a phase change enthalpy of 166.9 ± 1.2 J / g with only 2.8 K supercooling at sample sizes of 100 g . The PCM is stable over 500 repeated melting and solidification cycles at differential scanning calorimeter (DSC) scale with only small changes of the melting enthalpy and temperature.

  19. Thermophysical Characterization of MgCl2·6H2O, Xylitol and Erythritol as Phase Change Materials (PCM for Latent Heat Thermal Energy Storage (LHTES

    Directory of Open Access Journals (Sweden)

    Stephan Höhlein

    2017-04-01

    Full Text Available The application range of existing real scale mobile thermal storage units with phase change materials (PCM is restricted by the low phase change temperature of 58 ∘ C for sodium acetate trihydrate, which is a commonly used storage material. Therefore, only low temperature heat sinks like swimming pools or greenhouses can be supplied. With increasing phase change temperatures, more applications like domestic heating or industrial process heat could be operated. The aim of this study is to find alternative PCM with phase change temperatures between 90 and 150 ∘ C . Temperature dependent thermophysical properties like phase change temperatures and enthalpies, densities and thermal diffusivities are measured for the technical grade purity materials xylitol (C 5 H 12 O 5 , erythritol (C 4 H 10 O 4 and magnesiumchloride hexahydrate (MCHH, MgCl 2 · 6H 2 O. The sugar alcohols xylitol and erythritol indicate a large supercooling and different melting regimes. The salt hydrate MgCl 2 · 6H 2 O seems to be a suitable candidate for practical applications. It has a melting temperature of 115.1 ± 0.1 ∘ C and a phase change enthalpy of 166.9 ± 1.2 J / g with only 2.8 K supercooling at sample sizes of 100 g . The PCM is stable over 500 repeated melting and solidification cycles at differential scanning calorimeter (DSC scale with only small changes of the melting enthalpy and temperature.

  20. Optimised heat storage in an active slab of a residential building; Optimisation d'un stockage de chaleur en dalle active dans un immeuble d'habitation

    Energy Technology Data Exchange (ETDEWEB)

    Fromentin, A. [Swiss Federal Institute of Technology (EPFL), Laboratoire de systemes energetiques, Lausanne (Switzerland); Pahud, D.; Travaglini, G. [Scuola Universitaria Professionale della Svizzera Italiana, Dipartimento Costruzioni e Territorio, Laboratorio di energia, ecologia e economia, Canobbio (Switzerland)

    2000-07-01

    Two multi-family buildings of 20 flats each are planned in a Lausanne suburb in Switzerland with the objective of satisfying the so-called Minergie standard. Heating at a very low temperature is planned with 'active concrete plates'. They are plates in which pipes have been fixed for the circulation of a heat transfer fluid, acting as a heat emitter with a very large heat capacity, used as a heat storage device for a solar heating system. The solar heat output is evaluated with the solar collector array directly connected to the active concrete plates of the building. A diffusive duct ground heat store is included into the system without additional water buffer store, for the purpose of seasonal heat storage. The system's concepts are assessed and the system's thermal performance calculated. Based on the summary of the project results, preliminary sizing is possible. The TRNSYS system simulation programme is used to set up a calculation tool for the whole system including the building, the active concrete plates, the collector array and the diffusive heat store (when used in the system). A global heat balance is calculated. An optimal system size is found as a function of the solar fraction to be met. Simulations were also made to compare active-concrete-plate heating with heating floor, or uncovered solar absorbers with single-glazed solar collectors.

  1. Design of advanced solar homes aimed at net-zero annual energy consumption in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Athienitis, Andreas

    2010-09-15

    This paper overviews the design of three sustainable low or net-zero energy solar homes in Canada. The major features of the houses are: 1. direct gain passive solar design that emphasizes utilization of distributed thermal mass in the equatorial-facing part of the ground floor; 2. a building-integrated photovoltaic-thermal system (BIPV/T); 3. a two-stage ground-source heat pump used to heat/cool air in the house or an air source heat pump using BIPV/T air as the source to heat a storage tank; 4. a floor heating system integrated in the floor mass of the direct gain zone; 5. a multizone programmable thermostat.

  2. Modeling of hydrogen/deuterium dynamics and heat generation on palladium nanoparticles for hydrogen storage and solid-state nuclear fusion.

    Science.gov (United States)

    Tanabe, Katsuaki

    2016-01-01

    We modeled the dynamics of hydrogen and deuterium adsorbed on palladium nanoparticles including the heat generation induced by the chemical adsorption and desorption, as well as palladium-catalyzed reactions. Our calculations based on the proposed model reproduce the experimental time-evolution of pressure and temperature with a single set of fitting parameters for hydrogen and deuterium injection. The model we generated with a highly generalized set of formulations can be applied for any combination of a gas species and a catalytic adsorbent/absorbent. Our model can be used as a basis for future research into hydrogen storage and solid-state nuclear fusion technologies.

  3. Modeling of hydrogen/deuterium dynamics and heat generation on palladium nanoparticles for hydrogen storage and solid-state nuclear fusion

    Directory of Open Access Journals (Sweden)

    Katsuaki Tanabe

    2016-01-01

    Full Text Available We modeled the dynamics of hydrogen and deuterium adsorbed on palladium nanoparticles including the heat generation induced by the chemical adsorption and desorption, as well as palladium-catalyzed reactions. Our calculations based on the proposed model reproduce the experimental time-evolution of pressure and temperature with a single set of fitting parameters for hydrogen and deuterium injection. The model we generated with a highly generalized set of formulations can be applied for any combination of a gas species and a catalytic adsorbent/absorbent. Our model can be used as a basis for future research into hydrogen storage and solid-state nuclear fusion technologies.

  4. Fatty acid/poly(methyl methacrylate) (PMMA) blends as form-stable phase change materials for latent heat thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Alkan, Cemil; Sari, Ahmet [Gaziosmanpasa University, Department of Chemistry, Tasliciftlik, 60240 Tokat (Turkey)

    2008-02-15

    Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA), and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the most drawback which limits the utility area of them in thermal energy storage. The use of fatty acids as form-stable PCM will increase their feasibilities in practical LHTES applications due to reduced cost of the energy storage system. In this regard, a series of fatty acid/poly(methyl methacrylate) (PMMA) blends, SA/PMMA, PA/PMMA, MA/PMMA, and LA/PMMA were prepared as new kinds of form-stable PCMs by encapsulation of fatty acids into PMMA which acts as supporting material. The blends were prepared at different mass fractions of fatty acids (50, 60, 70, 80, and 90% w/w) to reach maximum encapsulation ratio. All blends were subjected to leakage test by heating the blends over the melting temperature of the PCM. The blends that do not allow leakage of melted PCM were identified as form-stable PCMs. The form-stable fatty acid/PMMA (80/20 wt.%) blends were characterized using optic microscopy (OM), viscosimetry, and Fourier transform infrared (FT-IR) spectroscopy methods, and the results showed that the PMMA was compatible with the fatty acids. In addition, thermal characteristics such as melting and freezing temperatures and latent heats of the form-stable PCMs were measured by using differential scanning calorimetry (DSC) technique and indicated that they had good thermal properties. On the basis of all results, it was concluded that form-stable fatty acid/PMMA blends had important potential for some practical LHTES applications such as under floor space heating of buildings and passive solar space heating of buildings by using wallboard, plasterboard or floor impregnated with a form-stable PCM due to their satisfying thermal properties, easily preparing in desired dimensions, direct usability without needing an add encapsulation and

  5. User manual for AQUASTOR: a computer model for cost analysis of aquifer thermal-energy storage oupled with district-heating or cooling systems. Volume II. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Huber, H.D.; Brown, D.R.; Reilly, R.W.

    1982-04-01

    A computer model called AQUASTOR was developed for calculating the cost of district heating (cooling) using thermal energy supplied by an aquifer thermal energy storage (ATES) system. the AQUASTOR Model can simulate ATES district heating systems using stored hot water or ATES district cooling systems using stored chilled water. AQUASTOR simulates the complete ATES district heating (cooling) system, which consists of two prinicpal parts: the ATES supply system and the district heating (cooling) distribution system. The supply system submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the ATES supply system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. The model combines the technical characteristics of the supply system and the technical characteristics of the distribution system with financial and tax conditions for the entities operating the two systems into one techno-economic model. This provides the flexibility to individually or collectively evaluate the impact of different economic and technical parameters, assumptions, and uncertainties on the cost of providing district heating (cooling) with an ATES system. This volume contains all the appendices, including supply and distribution system cost equations and models, descriptions of predefined residential districts, key equations for the cooling degree-hour methodology, a listing of the sample case output, and appendix H, which contains the indices for supply input parameters, distribution input parameters, and AQUASTOR subroutines.

  6. 15 Years of R&D in Central Solar Heating in Denmark

    DEFF Research Database (Denmark)

    Heller, Alfred

    2000-01-01

    Danish R&D activities during the last two decades in the field of Central Solar Heating Plants and Thermal Energy Storage Technologies are presented. The most relevant central solar heating plants (CSHPs), with and without seasonal storage, are examined and essential experiences highlighted....... The Saltum and Ry plants represent the type of CSHPs with preheating the return stream of a district heating net and no storage involved. The Marstal plant represents an alternative approach, connecting the CSHP to the delivery pipe for summer operation. Here the plant involves short-term storage...... and the application of variable flow that lead to novelties in the control strategy. The plant is described and experiences are analysed. The presented cases show that the technology, under special conditions, can be economically competitive with other heating technologies. Under normal conditions, public funding...

  7. Microstructure evolution of 7085 aluminum alloy with different initial deformation energy storage in fast and slow heating process

    Science.gov (United States)

    Xu, Xiaojing; Jia, Weijie; Tan, Cheng; Du, Donghui; Huang, Peng; Zhang, Chong

    2017-10-01

    The effect of initial deformation stored energy, target temperatures and heating rates on the microstructure and texture as well as the hardness and conductivity of 7085 aluminum alloy were investigated through hardness test, conductivity test, x-ray diffraction (XRD) analysis and electron backscatter diffraction scans (EBSD) measurement. The results revealed that with increasing the target temperature, the dislocation of the alloy was consumed, and the consumption of hot-pressed 7085 alloy was much faster than that of extruded alloy. Moreover, for the extruded alloy with low stored energy, the slow heating at rate of 3.6 °C h-1 could effectively suppress the recrystallization, while for hot-pressed 7085 alloy with high stored energy, the rapid heating at rate of 180 °C h-1 could not suppress the recrystallization. The different heat treatment also had great effect on the hardness and conductivity of 7085 alloy.

  8. Far-Infrared Emission Characteristics and Wear Comfort Property of ZrC-Imbedded Heat Storage Knitted Fabrics for Emotional Garments

    Directory of Open Access Journals (Sweden)

    Kim Hyun Ah

    2017-06-01

    Full Text Available This study examined the far-infrared emission characteristics and wear comfort properties of ZrC-imbedded heat storage knitted fabrics. For this purpose, ZrC-imbedded, heat storage PET (polyethylene terephthalate was spun from high-viscosity PET with imbedded ZrC powder on the core part and low-viscosity PET on the sheath part using a conjugated spinning method. ZrC-imbedded PET knitted fabric was also prepared and its physical properties were measured and compared with those of regular PET knitted fabric. In addition, ingredient analysis and the far-infrared emission characteristics of the ZrC-imbedded knitted fabrics were analyzed by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The thermal properties, moisture absorption, and drying properties of the ZrC-imbedded PET knitted fabric were measured and compared with those of the regular PET knitted fabric. The mechanical properties using the FAST (fabric assurance by simple testing system and the dye affinity of the ZrC-imbedded knitted fabric were also measured and compared with those of regular PET knitted fabric.

  9. CASTOR {sup registered} HAW28M - a high heat load cask for transport and storage of vitrified high level waste containers

    Energy Technology Data Exchange (ETDEWEB)

    Vossnacke, A.; Klein, K.; Kuehne, B. [GNS Gesellschaft fuer Nuklear-Service mbH/GNB, Essen (Germany)

    2004-07-01

    Within the German return programme for vitrified high level waste (HLW) from reprocessing at COGEMA and BNFL up to now 39 casks loaded with 28 containers each were transported back to Germany and are stored in the Interim Storage Facility Gorleben (TBL-G) for up to 40 years. For transport and storage in all but one case the GNB casks CASTOR {sup registered} HAW 20/28 CG have been used. This cask type is designed to accommodate 20 or 28 HLW containers with a total thermal power of 45 kW maximum. In the near future, among the high level waste, which has to be returned to Germany, there will be an increasing number of containers of which the heat capacity and radioactive inventory will exceed the technical limits of the CASTOR {sup registered} HAW 20/28 CG. Therefore GNB has started the development of a new cask generation, named CASTOR {sup registered} HAW28M, meeting these future requirements. The CASTOR {sup registered} HAW28M is especially developed for the transport of vitrified residues from France and Great Britain to Germany. It complies with the international regulations for type B packages according to IAEA (International Atomic Energy Agency). It is thus guaranteed that even in case of any accident the cask body and the lid system remain functional and the safe confinement of the radioactive contents remains intact during transport. The CASTOR {sup registered} HAW28M fulfills not only the requirements for transport but also the acceptance criteria of interim storage: radiation shielding, heat dissipation, safe confinement under both normal and hypothetical accident conditions. Storage buildings such as the TBL-G simply support the safety functions of the cask. The challenge for the development results from higher requirements of the technical specification, particularly related to fuel which is reprocessed. As a consequence of the reprocessing of fuel with increased enrichment and burn up, higher heat capacity and sophisticated shielding measures have to be

  10. The operation of small cogeneration plants and short-term storage for district heating and public electric power

    DEFF Research Database (Denmark)

    Ilkjær, J; Petersen, P.M.; Qvale, Einar Bjørn

    1989-01-01

    A theoretical investigation of the economics of cogeneration supplemented by warm-water storage and subjected to a three-step price schedule for electricity, has been carried out. Some general guidelines can be derived, but no simple design rules, such as those for cogeneration plants operating...

  11. Boiler heat pump with an integrated ice storage device. Final report; Heizkessel-Waermepumpe mit integriertem Eisspeicher. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Maier-Laxhuber, P.

    2001-03-01

    In the frame of the project boiler heat pump an energy-efficient heating system for space heating and service water is supposed to be developed. The system is a combination consisting of a state-of-the-art condensing value boiler and a thermally driven solid matter sorption heat pump with the natural and environmentally friendly working material pair water/zeolite. A heat exchanger concept has been found during the pre-phase based upon which a cost-effective and highly efficient boiler heat pump appears to be feasible. (orig.) [German] Im Rahmen des Projekts Heizkessel-Waermepumpe soll ein energieeffizientes Heizsystem fuer Raumheizungen und Brauchwasser entwickelt werden. Das System ist eine Kombination aus einem Brennwertkessel des aktuellen Standes der Technik und einer thermisch angetriebenen Feststoff-Sorptionswaermepumpe mit dem natuerlichen und umweltvertraeglichen Arbeitsstoffpaar Wasser/Zeolith. Im Rahmen der vorausgegangenen Vorphase wurde eine Waermetauscherkonzeption gefunden, die eine kostenguenstige und mit hohem Wirkungsgrad arbeitende Heizkessel-Waermepumpe moeglich erscheinen laesst. (orig.)

  12. Annual cycle solar energy utilization with seasonal storage. Part 7. Examination on design and control of the system partially recovering exhaust heat of heat pump; Kisetsukan chikunetsu ni yoru nenkan cycle taiyo energy riyo system ni kansuru kenkyu. 7. Bubuntekina hainetsu kaishu wo koryoshita baai no sekkei seigyoho no kento

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, H.; Okumiya, M. [Nagoya University, Nagoya (Japan)

    1996-10-27

    The capacity and performance of the existing system that recovers the overall heating and cooling exhaust heat completely into a seasonal storage tank and the system that discharges the exhaust heat slightly to the outside and recovers it partially were compared and investigated. The system uses a central single-duct discharge system as an air-conditioning system. A heat pump and a flat-plate solar collector installed on the roof of a building are used as the heat source. The seasonal storage tank in the ground just under the building is a cylindrical water tank of 5 m deep with the concrete used as body. The upper surface of a storage tank is heat-insulated by a stylo-platform of 200 mm, and the lower side surface by a stylo-platform of 100 mm. Calculation when the difference in temperature used in a seasonal storage tank is set to 35{degree}C and 25{degree}C was performed for the system that has two control methods. The overall exhaust heat recovery system is almost the same in energy performance as the partial exhaust heat recovery system. The partial exhaust heat recovery system is more advantageous on the economic side. 4 refs., 6 figs., 3 tabs.

  13. Thermal energy storage

    Science.gov (United States)

    1980-01-01

    The planning and implementation of activities associated with lead center management role and the technical accomplishments pertaining to high temperature thermal energy storage subsystems are described. Major elements reported are: (1) program definition and assessment; (2) research and technology development; (3) industrial storage applications; (4) solar thermal power storage applications; and (5) building heating and cooling applications.

  14. Enhanced geothermal systems (EGS) with CO2 as heat transmission fluid--A scheme for combining recovery of renewable energy with geologic storage of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K.; Spycher, N.

    2009-05-01

    It has been suggested that enhanced geothermal systems (EGS) may be operated with supercritical CO{sub 2} instead of water as heat transmission fluid (D.W. Brown, 2000). Such a scheme could combine recovery of geothermal energy with simultaneous geologic storage of CO{sub 2}, a greenhouse gas. At geothermal temperature and pressure conditions of interest, the flow and heat transfer behavior of CO{sub 2} would be considerably different from water, and chemical interactions between CO{sub 2} and reservoir rocks would also be quite different from aqueous fluids. This paper summarizes our research to date into fluid flow and heat transfer aspects of operating EGS with CO{sub 2}. (Chemical aspects of EGS with CO{sub 2} are discussed in a companion paper; Xu and Pruess, 2010.) Our modeling studies indicate that CO{sub 2} would achieve heat extraction at larger rates than aqueous fluids. The development of an EGS-CO{sub 2} reservoir would require replacement of the pore water by CO{sub 2} through persistent injection. We find that in a fractured reservoir, CO{sub 2} breakthrough at production wells would occur rapidly, within a few weeks of starting CO{sub 2} injection. Subsequently a two-phase water-CO{sub 2} mixture would be produced for a few years,followed by production of a single phase of supercritical CO{sub 2}. Even after single-phase production conditions are reached,significant dissolved water concentrations will persist in the CO{sub 2} stream for many years. The presence of dissolved water in the production stream has negligible impact on mass flow and heat transfer rates.

  15. An investigation of a jet-pump thermal (ice) storage system powered by low-grade heat

    OpenAIRE

    Worall, Mark

    2001-01-01

    This thesis investigates a novel combination of a jet-pump refrigeration cycle and a thermal (ice) storage (TIS) system that could substantially reduce the electrical energy requirements attributable to comfort cooling.Two methods of TIS were identified; spray ice TIS would use evaporative freezing to store ice on a vertical surface,and encapsulated ice TIS would freeze a bed of encapsulated elements by sublimation freezing.Thestudy also investigates jet-pump refrigeration at partload and a ...

  16. The effect the effectiveness of the liquid suction heat exchanger to performance of cold storage with refrigerant R22, R404A and R290/R600a

    Science.gov (United States)

    Prayudi, Nurhasanah, Roswati; Diantari, Retno Aita

    2017-01-01

    Storage space requirements with a large refrigeration capacity they use refrigerants types R22 and R404A. This research to develop alternative technologies to meet the needs of storage space with a large refrigeration capacity. Liquid suction subcooling technology is typically used to obtain improve refrigeration effect at vapor compression refrigeration system. Liquid suction heat exchanger subcooling used a type of tube in tube heat exchanger installed between the condenser and the capillary tube before entering the evaporator. Refrigerant used in this research is R22, R404A, and mixture refrigerant R290/R600a [50:50]. In steady state condition with subcooling temperature evaporator with R290/R600a lower reaches -30°C, lower than R404a and R22 is -24°C and -22°C. Liquid suction heat exchanger subcooling effect on ΔTsub. The cooling effect by the mixture refrigerant of R290/R600a greater than R404a and R22, and liquid suction heat exchanger increase refrigeration capacity index (RCI). The average increase in RCI respectively 3.91%, 7.78%, and 11.87%. Work compressor and compressor work index (CWI) with a mixture refrigerant of R290/R600a greater than R404a and R22, the average work compressor and the working compressor index is greatest mixture refrigerant R290/R600a. CWI respectively is an average of 5.68%, 8.82%, and 11.82%. The average COP, their, liquid suction heat exchanger, respectively are 3.38, 3.18 and 2.63. COPRS with a mixture refrigerant of R290/R600a [50:50] is bigger than the R22 and R404a, and the average COPRS is 5:01%, 5.95%, and 7:41%. A mixture refrigerant R290/R600a [50:50] have the same characteristics as R404a, which can be used as a substitute for refrigerant R22 and R404A.

  17. Energy saving and waste heat recovery within the refrigeration and cold storage sector in Lithuania. Final report for fact finding mission

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    This is the final report for the Fact Finding Mission, which is the first part of the demonstration project in Energy Saving and Waste Heat recovery within the Refrigeration and Cold Storage Sector in Lithuania. The purpose of this first part of the project, The Fact Finding Mission, is the identification and recommendation of one (possibly two) companies for implementation of a demonstration project. The recommendation is based partly on the strictly technical possibilities of implementation of a demonstration project within Energy Saving and Waste Heat Recovery, but also on the interest of the companies in the implementation of this type of measures as well as their possibilities of financing. The result of The Fact Finding Mission is a recommendation for the implementation of a demonstration project at the slaughtering and meat processing company `Taurage Maistas`, for which it is estimated that there are good possibilities of implementing measures for reduction of the energy consumption and utilisation of the generated waste heat. Also, the company is considered by the authorities to be a financially well functioning company. For examples a privatisation process has already been carried out and within a few years the company has turned a deficit to a profit and increased the turnover by approx. 33%. (EG)

  18. Solarthermie 2000 - Partial programme 3: Solar district heat - solar campus Juelich, feasibility study of the seasonal heat storage; Solarthermie 2000, Teilprogramm 3: Solare Nahwaerme - Solar-Campus Juelich, Machbarkeitsuntersuchung des saisonalen Waermespeichers

    Energy Technology Data Exchange (ETDEWEB)

    Braxein, A. [Iwu - Ingenieurgesellschaft fuer Wasser und Umwelt mbH, Aachen (Germany); Spaete, F.; Repschlaeger, H. [Solar-Inst. Juelich (Germany); Friedel, J. [Stadtwerke Juelich (Germany)

    1998-12-31

    The heart of the solar-assisted district heating system for the solar campus Juelich is going to be a seasonal underground store with a capacity of 2,500 cubic metres, e.g. a rather small long-term storage. The aim of the project was to prove the technical and financial feasibility of the underground store by developing a building concept for the storage and to determine whether this concept was also suitable for larger storage facilities. The design of the floating lid and the suitability of various building materials were studied by means of a physical model. The resulting storage concept shows an underground storage pit whose shape is an inverted square pyramid base with a seal of double-layer PP-foil and a thermal insulation of pressure-resistant mineral wool in the upper part. The lid consists of 16 square walk-on floating containers with an edge length of 6.50 metres and a height of 1.0 metre each. Tests and calculations showed that the concept can be realised. The building costs for the small storage with a capacity of 2,500 cubic metres will amount to approx. DM 370 per cubic metre, costs for larger volumes of 25,000 cubic metres will amount to approx. DM 150 DM per cubic metre of water stored. (orig.) [Deutsch] Das Kernstueck der solargestuetzten Nahwaermeversorgung fuer den Solar-Campus Juelich soll ein 2500 m{sup 3} grosser, saisonaler Erdbeckenspeicher bilden, also ein relativ kleiner Langzeitspeicher. Ziel des Vorhabens war, die technische und finanzielle Machbarkeit des geplanten Erdbeckenspeichers durch ein baureifes Speicherkonzept nachzuweisen sowie die Uebertragbarkeit auf grosse saisonale Speicher gleicher Bauart zu untersuchen. Die konstruktive Ausbildung der schwimmenden Deckelkonstruktion sowie die Eignung verschiedener Baumaterialien wurden mit Hilfe eines physikalischen Modells untersucht. Das resultierende Speicherkonzept sieht einen Erdbeckenspeicher in Form eines umgedrehten, quadratischen Pyramidenstumpfes mit einer Abdichtung aus

  19. The Development of an INL Capability for High Temperature Flow, Heat Transfer, and Thermal Energy Storage with Applications in Advanced Small Modular Reactors, High Temperature Heat Exchangers, Hybrid Energy Systems, and Dynamic Grid Energy Storage C

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaodong [The Ohio State Univ., Columbus, OH (United States); Zhang, Xiaoqin [The Ohio State Univ., Columbus, OH (United States); Kim, Inhun [The Ohio State Univ., Columbus, OH (United States); O' Brien, James [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-10-01

    The overall goal of this project is to support Idaho National Laboratory in developing a new advanced high temperature multi fluid multi loop test facility that is aimed at investigating fluid flow and heat transfer, material corrosion, heat exchanger characteristics and instrumentation performance, among others, for nuclear applications. Specifically, preliminary research has been performed at The Ohio State University in the following areas: 1. A review of fluoride molten salts’ characteristics in thermal, corrosive, and compatibility performances. A recommendation for a salt selection is provided. Material candidates for both molten salt and helium flow loop have been identified. 2. A conceptual facility design that satisfies the multi loop (two coolant loops [i.e., fluoride molten salts and helium]) multi purpose (two operation modes [i.e., forced and natural circulation]) requirements. Schematic models are presented. The thermal hydraulic performances in a preliminary printed circuit heat exchanger (PCHE) design have been estimated. 3. An introduction of computational methods and models for pipe heat loss analysis and cases studies. Recommendations on insulation material selection have been provided. 4. An analysis of pipe pressure rating and sizing. Preliminary recommendations on pipe size selection have been provided. 5. A review of molten fluoride salt preparation and chemistry control. An introduction to the experience from the Molten Salt Reactor Experiment at Oak Ridge National Laboratory has been provided. 6. A review of some instruments and components to be used in the facility. Flowmeters and Grayloc connectors have been included. This report primarily presents the conclusions drawn from the extensive review of literatures in material selections and the facility design progress at the current stage. It provides some useful guidelines in insulation material and pipe size selection, as well as an introductory review of facility process and components.

  20. Effect of water storage on the flexural strength of heat-cured denture base resin reinforced with stick (s glass fibers

    Directory of Open Access Journals (Sweden)

    Ankit Galav

    2017-01-01

    Full Text Available Background: Flexural strength (FS of denture base resins (DBRs had been improved by reinforcing it with different glass fibers. However, a limited data are available on the effect of glass fiber reinforcement with conventional heat-cured resin after prolonged water storage. Aims and Objectives: This study aimed to evaluate the reinforcing effect of novel S-glass and nylon fibers on the FS of acrylic DBRs. It also aimed to evaluate the effect of glass fiber reinforcement on the FS of acrylic DBRs after a prolonged storage in water. Materials and Methods: One hundred and sixty identical specimens were fabricated in specially designed molds according to the manufacturer's instructions. The three experimental groups were prepared consisting of conventional (unreinforced acrylic resin, novel S-glass fiber-reinforced and nylon fiber-reinforced acrylic resin. The specimens were fabricated in a standardized fashion for each experimental group. Each group was further subdivided into two groups on the basis of storage conditions (dry and wet. FS was tested using a three-point universal testing machine at a crosshead speed of 5 mm/min. Glass fiber-reinforced group was further tested after prolonged storage in distilled water. Entered data were statistically analyzed with one-way ANOVA and least significant difference post hoc test. Results: In this study, statistically significant differences were noted in the FS of all the groups. S-glass fiber-reinforced group had highest FS compared to the other two groups (P < 0.001. Nylon fiber-reinforced group had lowest FS. All the groups stored in distilled water revealed a decrease in strength compared to those stored in dry atmosphere. Among wet specimens, those stored for 3 weeks had a significantly higher FS than those stored at one and 2 weeks (P < 0.01. Conclusion: Within the limitations of this investigation, the FS of heat-cured acrylic DBR was improved after reinforcement with glass fibers. It can be

  1. Long-term modelling of Carbon Capture and Storage, Nuclear Fusion, and large-scale District Heating

    DEFF Research Database (Denmark)

    Grohnheit, Poul Erik; Korsholm, Søren Bang; Lüthje, Mikael

    2011-01-01

    on nuclear fusion and the Pan European TIMES model, respectively. In the next decades CCS can be a driver for the development and expansion of large-scale district heating systems, which are currently widespread in Europe, Korea and China, and with large potentials in North America. If fusion will replace...

  2. Effects of packaging and heat transfer kinetics on drug-product stability during storage under uncontrolled temperature conditions.

    Science.gov (United States)

    Nakamura, Toru; Yamaji, Takayuki; Takayama, Kozo

    2013-05-01

    To predict the stability of pharmaceutical preparations under uncontrolled temperature conditions accurately, a method to compute the average reaction rate constant taking into account the heat transfer from the atmosphere to the product was developed. The average reaction rate constants computed with taken into consideration heat transfer (κ(re) ) were then compared with those computed without taking heat transfer into consideration (κ(in) ). The apparent thermal diffusivity (κ(a) ) exerted some influence on the average reaction rate constant ratio (R, R = κ(re) /κ(in) ). In the regions where the κ(a) was large (above 1 h(-1) ) or very small, the value of R was close to 1. On the contrary, in the middle region (0.001-1 h(-1) ), the value of R was less than 1.The κ(a) of the central part of a large-size container and that of the central part of a paper case of 10 bottles of liquid medicine (100 mL) fell within this middle region. On the basis of the above-mentioned considerations, heat transfer may need to be taken into consideration to enable a more accurate prediction of the stability of actual pharmaceutical preparations under nonisothermal atmospheres. Copyright © 2013 Wiley Periodicals, Inc.

  3. Experimental Investigation of Latent Heat Thermal Energy Storage for Bi-Modal Solar Thermal Propulsion (Briefing Charts)

    Science.gov (United States)

    2014-07-01

    performance of 28,100 kg, shuttle launched spacecraft for LEO-GEO transfer Engine Type LO2-H2 Ion Solar 1 Solar 2 ΔV (m/s) 4,270 5,850 5,850 4,800...Comparison Metrics Solar Thermal w/o Energy Storage Chemical Thrusters Electric Propulsion • Eliminated PCM and TPV • Reduced solar collector ...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) July 2014 2. REPORT TYPE Briefing

  4. A method for load management in low voltage grids. Application from e-mobility to heat storage; Verfahren zum Lastmanagement in Niederspannungsnetzen. Anwendung von E-Mobility bis Waermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Tobias; Schegner, Peter [TU Dresden (Germany). IEEH; Hable, Matthias [ENSO NETZ GmbH, Dresden (Germany)

    2012-07-01

    With the expected charging characteristic of e-mobility a considerable load peak during the night is expected. The paper describes the application of a modified maximal rectangle algorithm to determine the optimal starting times for charging to realise a flat load curve. The load characteristic of e-mobility is similar to heat storage. This allows to use the currently widely spread heat storage devices as example for developing and testing methods for optimized load management in low voltage networks. It is shown that the developed optimization algorithm finds solutions close to the global optimum even in large networks ({approx} 25000 devices) with low requirements of calculation time (< 1 min). (orig.)

  5. Proof of concept of the CaO/Ca(OH)2 reaction in a continuous heat-exchanger BFB reactor for thermochemical heat storage in CSP plants

    Science.gov (United States)

    Rougé, Sylvie; Criado, Yolanda A.; Huille, Arthur; Abanades, J. Carlos

    2017-06-01

    The CaO/Ca(OH)2 hydration/dehydration reaction has long been identified as a attractive method for storing CSP heat. However, the technology applications are still at laboratory scale (TG or small fixed beds). The objective of this work is to investigate the hydration and dehydration reactions performance in a bubbling fluidized bed (BFB) which offers a good potential with regards to heat and mass transfers and upscaling at industrial level. The reactions are first investigated in a 5.5 kW batch BFB, the main conditions are the bed temperature (400-500°C), the molar fraction of steam in the fluidizing gas (0-0.8), the fluidizing gas velocity (0.2-0.7 m/s) and the mass of lime in the batch (1.5-3.5 kg). To assist in the interpretation of the experimental results, a standard 1D bubbling reactor model is formulated and fitted to the experimental results. The results indicate that the hydration reaction is mainly controlled by the slow kinetics of the CaO material tested while significant emulsion-bubble mass-transfer resistances are identified during dehydration due to the much faster dehydration kinetics. In the continuity of these preliminary investigations, a continuous 15.5 kW BFB set-up has been designed, manufactured and started with the objective to operate the hydration and dehydration reactions in steady state during a few hours, and to investigate conditions of faster reactivity such as higher steam molar fractions (up to 1), temperatures (up to 600°C) and velocities (up to 1.5 m/s).

  6. Energy conservation by short-term storage of heat and cold. Feasibility study of technique and applications; Energiebesparing door korte termijn opslag van warmte/koude. Haalbaarheidsstudie techniek en toepassingen

    Energy Technology Data Exchange (ETDEWEB)

    Steen, D.; Kee, R.J.M. [IHN Leeuwarden, Leeuwarden (Netherlands)

    1997-03-01

    The options of process integration by means of short-term storage of heat or cold have been studied. First, an overview was made of the possibilities to apply short-term storage for energy consumers in the Netherlands, including an estimation of the energy saving potential. Next, existing short-term techniques were inventoried. Subsequently, a design procedure was drafted and a computer program was developed by means of which the dimensions of a short-term thermal-stratified storage can be determined. Finally, the results of three feasibility studies at a dairy industry, a textile industry, and for the slaughterhouse and meat sector are presented. 20 refs.

  7. ANTICIPATED COSTEFFECTIVE EFFECT FROM APPLICATION OF THE EJECTOR HEAT EXCHANGER FOR CONDENSATION OF LIGHT FRACTION HYDROCARBON ON THE PETROLEUM STORAGE DEPOT

    Directory of Open Access Journals (Sweden)

    I. Butovskyi

    2016-08-01

    Full Text Available Loss control of oil products is the one of the relevant paths of saving of the fuel and energy resources play a crucial role in development of economics. Now a great many of different procedures of a choice of means of reduction of oil losses and petrol from evaporation are known. However the one part from them did not allow for value of these means and expenditures for them maintenance, another – did not allow for diversity of implementation of means of reduction of losses, third – uses outdated, now, the criterion. In the conditions of petroleum storage depots, as a rule, usage of ejector systems of trapping of light fraction are more preferential, than other hardware’s of reduction of losses. The positive effect from application of an ejector heat exchanger for preventing of losses of petroleum products are calculate.

  8. Investigation of the self-heating and spontaneous ignition of refuse-derived fuel (RDF) during storage.

    Science.gov (United States)

    Yasuhara, Akio; Amano, Yuko; Shibamoto, Takayuki

    2010-07-01

    Refuse-derived fuel (RDF)-RDF-5 according to ASTM guidelines-derived from municipal solid waste and other waste materials, has been prepared as a fuel source for power plants in Japan. RDF has been known as a stable and safe solid-fuel. However, some spontaneous ignition incidents occurred during storage of RDF in certain facilities. In the present study, the storage conditions, which might induce the spontaneous ignition in RDF samples, was investigated to understand and prevent this phenomenon. When the initial temperature of RDF sample was consistent, higher water content and shorter induction times was observed (e.g., the induction times of select RDF samples with 5.8% and 16.7% water content, was 446 and 270 min, respectively). Also, the induction time was affected by the size of a RDF sample. No relationship between bacterial fermentation and spontaneous ignition was observed. The linear relationship between the induction time and the inverse of the initial temperature of the RDF sample was obtained in the Arrhenius equation. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  9. Study on improving the heat storage property of Ba(OH)2·8H2O with paraffin

    Science.gov (United States)

    Cui, Kaixuan; Liu, Liqiang; Sun, Mingjie

    2017-12-01

    Barium hydroxide octahydrate is the crystalline hydration salt with the highest latent heat density within the phase change temperature interval of 0–120 °C and it has a broad application prospect as a phase-change material (PCM). Firstly, red copper test tube was used for the melting—solidification heat cycle experiment in this paper, which was verified by the corrosion experiment of barium hydroxide solution. After the thermogravimetric analysis, it is found that paraffin can effectively reduce the evaporation escape of barium hydroxide octahydrate crystal water within 100 °C. Repeated heat cycle experiments indicated that the paraffin with larger coverage mass fraction can reduce the inhibiting effect of barium hydroxide octahydrate crystal water more obviously. X-ray diffraction analysis indicated that the phase composition of the barium hydroxide octahydrate sample covered with 50 wt% paraffin nearly had no change, while the sample not covered with paraffin has the weight loss ratio of 34.67% and reacted with CO2 in the air, generating BaCO3. In summary, paraffin can not only inhibit the evaporation of crystal water, but also effectively isolate the air to prevent barium hydroxide octahydrate from denaturation. This greatly improved the practicability of barium hydroxide octahydrate as a PCM, laying a good foundation for the further application of barium hydroxide octahydrate.

  10. Heat stress of two tropical seagrass species during low tides - impact on underwater net photosynthesis, dark respiration and diel in situ internal aeration.

    Science.gov (United States)

    Pedersen, Ole; Colmer, Timothy D; Borum, Jens; Zavala-Perez, Andrea; Kendrick, Gary A

    2016-06-01

    Seagrasses grow submerged in aerated seawater but often in low O2 sediments. Elevated temperatures and low O2 are stress factors. Internal aeration was measured in two tropical seagrasses, Thalassia hemprichii and Enhalus acoroides, growing with extreme tides and diel temperature amplitudes. Temperature effects on net photosynthesis (PN ) and dark respiration (RD ) of leaves were evaluated. Daytime low tide was characterized by high pO2 (54 kPa), pH (8.8) and temperature (38°C) in shallow pools. As PN was maximum at 33°C (9.1 and 7.2 μmol O2  m(-2) s(-1) in T. hemprichii and E. acoroides, respectively), the high temperatures and reduced CO2 would have diminished PN , whereas RD increased (Q10 of 2.0-2.7) above that at 33°C (0.45 and 0.33 μmol O2  m(-2)  s(-1) , respectively). During night-time low tides, O2 declined resulting in shoot base anoxia in both species, but incoming water containing c. 20 kPa O2 relieved the anoxia. Shoots exposed to 40°C for 4 h showed recovery of PN and RD , whereas 45°C resulted in leaf damage. These seagrasses are 'living near the edge', tolerant of current diel O2 and temperature extremes, but if temperatures rise both species may be threatened in this habitat. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  11. Technology data for energy plants. Generation of electricity and district heating, energy storage and energy carrier generation and conversion

    Energy Technology Data Exchange (ETDEWEB)

    2012-05-15

    The Danish Energy Agency and Energinet.dk, the Danish electricity transmission and system operator, have at regular intervals published a catalogue of energy producing technologies. The previous edition was published in June 2010. This report presents the results of the most recent update. The primary objective of publishing a technology catalogue is to establish a uniform, commonly accepted and up-to-date basis for energy planning activities, such as future outlooks, evaluations of security of supply and environmental impacts, climate change evaluations, and technical and economic analyses, e.g. on the framework conditions for the development and deployment of certain classes of technologies. With this scope in mind, it has not been the intention to establish a comprehensive catalogue, including all main gasification technologies or all types of electric batteries. Only selected, representative, technologies are included, to enable generic comparisons of e.g. thermal gasification versus combustion of biomass and electricity storage in batteries versus hydro-pumped storage. It has finally been the intention to offer the catalogue for the international audience, as a contribution to similar initiatives aiming at forming a public and concerted knowledge base for international analyses and negotiations. A guiding principle for developing the catalogue has been to rely primarily on well-documented and public information, secondarily on invited expert advice. Since many experts are reluctant in estimating future quantitative performance data, the data tables are not complete, in the sense that most data tables show several blank spaces. This approach has been chosen in order to achieve data, which to some extent are equivalently reliable, rather than to risk a largely incoherent data set including unfounded guesstimates. The current update has been developed with an unbalanced focus, i.e. most attention to technologies which are most essential for current and short

  12. Performance Evaluation of HP/ORC (Heat Pump/Organic Rankine Cycle) System with Optimal Control of Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    energy in periods of no thermal energy demand and reverses the heat pump cycle to supply electrical power. A dynamic model based on empirical data of this system is used to determine the annual performance. Furthermore, this work assesses the benefits of different control strategies that address...... of the users. Results show that real load control logic can lessen the adverse effects of cycling in the compressor of the system as well as increase the thermal demand (up to 33%) and the electrical demand (max. 8.4%) covered by renewable energy (solar). However, the extension of these improvements is highly...

  13. Enhanced Thermal Properties of Novel Latent Heat Thermal Storage Material Through Confinement of Stearic Acid in Meso-Structured Onion-Like Silica

    Science.gov (United States)

    Gao, Junkai; Lv, Mengjiao; Lu, Jinshu; Chen, Yan; Zhang, Zijun; Zhang, Xiongjie; Zhu, Yingying

    2017-08-01

    Meso-structured onion-like silica (MOS), which had a highly ordered, onion-like multilayer; large surface area and pore volume; and highly curved mesopores, were synthesized as a support for stearic acid (SA) to develop a novel shape-stabilized phase change material (SA/MOS). The characterizations of SA/MOS were studied by the analysis technique of scanning electron microscope, infrared spectroscopy, x-ray diffraction, differential scanning calorimeter (DSC), and thermal gravimetry analysis (TGA). The results showed that the interaction between the SA and the MOS was physical adsorption and that the MOS had no effect on the crystal structure of the SA. The DSC results suggested that the melting and solidifying temperature of the SA/MOS were 72.7°C and 63.9°C with a melting latent heat of 108.0 J/g and a solidifying latent heat of 126.0 J/g, respectively, and the TGA results indicated that the SA/MOS had a good thermal stability. All of the results demonstrated that the SA/MOS was a promising thermal energy storage material candidate for practical applications.

  14. Enhanced Thermal Properties of Novel Latent Heat Thermal Storage Material Through Confinement of Stearic Acid in Meso-Structured Onion-Like Silica

    Science.gov (United States)

    Gao, Junkai; Lv, Mengjiao; Lu, Jinshu; Chen, Yan; Zhang, Zijun; Zhang, Xiongjie; Zhu, Yingying

    2017-12-01

    Meso-structured onion-like silica (MOS), which had a highly ordered, onion-like multilayer; large surface area and pore volume; and highly curved mesopores, were synthesized as a support for stearic acid (SA) to develop a novel shape-stabilized phase change material (SA/MOS). The characterizations of SA/MOS were studied by the analysis technique of scanning electron microscope, infrared spectroscopy, x-ray diffraction, differential scanning calorimeter (DSC), and thermal gravimetry analysis (TGA). The results showed that the interaction between the SA and the MOS was physical adsorption and that the MOS had no effect on the crystal structure of the SA. The DSC results suggested that the melting and solidifying temperature of the SA/MOS were 72.7°C and 63.9°C with a melting latent heat of 108.0 J/g and a solidifying latent heat of 126.0 J/g, respectively, and the TGA results indicated that the SA/MOS had a good thermal stability. All of the results demonstrated that the SA/MOS was a promising thermal energy storage material candidate for practical applications.

  15. Effect of Heat Treatment and Salt Concentration on Free Amino Acids Composition of Sudanese Braided (Muddaffara Cheese during Storage

    Directory of Open Access Journals (Sweden)

    Mohamed O. E. Altahir

    2014-08-01

    Full Text Available The aim of this study was to assess the effect of heat treatment and salt concentrations (0, 5, and 10% on the free amino acids (FAA composition of Sudanese braided cheese (BC ripened for up to 3 months at 5±2°C. Heat and salt concentration significantly affected the FAA of braided cheese. The free amino acids concentrations of BC ripened in 0%, 5%, and 10% salted whey (SW were significantly fluctuated. Under ripening conditions tested (salt level + time, braided cheese made from pasteurized milk (BCPM had consistently lower values of FAA than braided cheese made from raw milk (BCRM. In fresh cheese, the major FAA in BCRM were Glu (36.12 nmol/ml, Leu (26.77nmol/ml and Lys (14.51 nmol/ml while the major ones in BCPM were Lys (2.94 nmol/ml and Ala (2.45 nmol/ml. BCPM stored in 10% SW had shorter quality life compared to that stored in 5% salted whey.

  16. Natural heat storage in a brine-filled solar pond in the Tully Valley of central New York

    Science.gov (United States)

    Hayhurst, Brett; Kappel, William M.

    2014-01-01

    The Tully Valley, located in southern Onondaga County, New York, has a long history of unusual natural hydrogeologic phenomena including mudboils (Kappel, 2009), landslides (Tamulonis and others, 2009; Pair and others, 2000), landsurface subsidence (Hackett and others, 2009; Kappel, 2009), and a brine-filled sinkhole or “Solar pond” (fig. 1), which is documented in this report. A solar pond is a pool of salty water (brine) which stores the sun’s energy in the form of heat. The saltwater naturally forms distinct layers with increasing density between transitional zones (haloclines) of rapidly changing specific conductance with depth. In a typical solar pond, the top layer has a low salt content and is often times referred to as the upper convective zone (Lu and others, 2002). The bottom layer is a concentrated brine that is either convective or temperature stratified dependent on the surrounding environment. Solar insolation is absorbed and stored in the lower, denser brine while the overlying halocline acts as an insulating layer and prevents heat from moving upwards from the lower zone (Lu and others, 2002). In the case of the Tully Valley solar pond, water within the pond can be over 90 degrees Fahrenheit (°F) in late summer and early fall. The purpose of this report is to summarize observations at the Tully Valley brine-filled sinkhole and provide supplemental climate data which might affect the pond salinity gradients insolation (solar energy).

  17. Doping magnesium hydroxide with sodium nitrate: a new approach to tune the dehydration reactivity of heat-storage materials.

    Science.gov (United States)

    Shkatulov, Alexandr; Krieger, Tamara; Zaikovskii, Vladimir; Chesalov, Yurii; Aristov, Yuri

    2014-11-26

    Thermochemical energy storage (TES) provides a challenging approach for improving the efficiency of various energy systems. Magnesium hydroxide, Mg(OH)2, is known as a suitable material for TES at temperature T>300 °C. In this work, the thermal decomposition of Mg(OH)2 in the absence and presence of sodium nitrate (NaNO3) is investigated to adapt this material for TES at T300 °C in vapor atmosphere) than a pure Mg(OH)2; (3) the morphology of the dehydration product (MgO) dramatically changes. Differential scanning calorimetry, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrational spectroscopy (IR and Raman) are used to study the observed effects and to elucidate possible ways the NaNO3 influences the Mg(OH)2 dehydration and morphology of the dehydration product. The mechanism involving a chemical interaction between the salt and the hydroxide accompanied by nitrate embedding into brucite layers is discussed.

  18. Heating plan for Denmark; Varmeplan Danmark

    Energy Technology Data Exchange (ETDEWEB)

    2008-10-15

    Today, district heating supplies 46% of the Danish net heating demand. The present report analyses whether it will be feasible for Denmark to extend the share of district heating or whether other alternatives are better. The analysis relates to the government's and parliament's plans to reduce Denmark's CO{sub 2} emission in the short term as well as to transfer the energy supply to be based fully on renewable energy sources in the long term. Calculations show that CO{sub 2} emissions from the heating sector can be halved by the year 2020, and that the sector can become almost CO{sub 2} neutral by around the year 2030. The prognosis for the year 2020 is 1) district heating supply is extended from 46% to about 60% of the market; 2) the consumers save further 25% of heat consumption and lowers the return temperature; 3) about 70% of all new buildings are supplied with district heat or heat from central heating plants; 4) the use of surplus heat during summer and the competition between different heating sources are increased through further coupling of the district heating systems; 5) the district heat production is extended using more heat storage, more renewable energy, and surplus heat, including heat from use of waste, cogeneration, biogas, solar energy, biomass, geothermal energy, heat pumps, and electric boilers for using surplus wind energy; 6) the CO{sub 2} emission from the heating sector is halved. To achieve this prognosis there are several challenges. The local governments must find a suitable delimitation between district heating and individual heat pumps where the advantages of district heating (efficiency and security of supply) are balanced against the relatively large investments in distribution networks. The district heating supplying sector must make the heat supply more efficient taking into account the consumers' possibilities to save heat consumption. The building owners must reduce the consumption of electric power, heat

  19. Heat Emission from a Burning Cigarette

    OpenAIRE

    Miura K; Nagao A; Ueyama K

    2014-01-01

    We investigated the relationship between the smoldering burn rate and the heat transfer from a burning cigarette by measuring the heat emitted by radiation and convection, separately. The net heat generated and the net heat emitted by a burning cigarette did not vary with a change of the cigarette smoldering burn rate. The total heat emitted from a statically burning cigarette was about 50% of the total combustion heat. About 50% of the heat emitted was released as radiation heat. The smolder...

  20. NA-NET numerical analysis net

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J. [Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science]|[Oak Ridge National Lab., TN (United States); Rosener, B. [Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host ``na-net.ornl.gov`` at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message ``send index`` to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user`s perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.